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Disk Operating System Version 3.10

Reference

Programming Family

Personal

Computer

Software

First edition (February 1985)

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About This Book

Read This First

This manual explains how to use the IBM Personal
Computer Disk Operating System Version 3.10.
Information is given on how to:

Refer to DOS files

Prepare your fixed disk for DOS

Use directories to organize your disks

Use redirection, piping, and filters with standard
input and standard output

Use DOS commands

Create and edit files using EDLIN

Link programs with the LINKER.

First Time Users

Before using your DOS diskette for the first time, read
the sections "Using Your DOS Diskettes" and "About
Diskette Drives and Diskettes" in Chapter 1 of this
book.

111

Experienced Users

Experienced programmers can use this book together
with the IBM DOS Technical Reference to develop
application programs. Information is provided on:

Installable device drivers

Cursor control sequences that control cursor
positioning and reassign keyboard keys

File Management

DOS disk allocation

DOS interrupts and function calls

DOS control blocks and work area

Executing commands from within an application

Fixed disk information

EXE file structure and loading

DOS memory management

DEBUG

Terms Used

The terms "diskette," "fixed disk," and "disk" are used
throughout this book. Where "diskette" is used, it
applies only to diskette drives and diskettes. Where
"fixed disk" is used, it applies only to the IBM
non-removable fixed disk drive. Where "disk" is used,
it applies to both fixed disks and diskettes.

The terms "source" and "target" are used to describe
diskettes and drives. The source refers to the original
or first diskette or drive, and the target refers to the
second or new diskette or drive.

The terms "local" and "remote" describe the location
of a disk, directory or printer relative to your computer.
A local disk, directory, or printer is on your computer.
A remote disk, directory, or printer is on a network
computer.

Using Applications with DOS 3.10

To use applications with DOS Version 3.10, you need
to follow the setup procedures given in the IBM
Application Setup Guide. Do not follow the setup
procedures given in your application manual.

How This Book is Organized

This book has 10 chapters and one appendix.

Chapter 1 is an introduction to DOS Version 3.10. It
contains information about diskette types and
compatibility. The new features of DOS Version 3.10
are also discussed.

Chapter 2 describes the DOS file specification.
Information on valid filename characters and global
filename characters is described.

Chapter 3 gives detailed instructions on how to prepare
your fixed disk for use by DOS.

Chapter 4 describes system configuration. It contains
the commands that you can include in a CONFIG.SYS
file to configure your system.

Chapter 5 describes the use of tree-structured
directories.

Chapter 6 describes how to use redirection, piping, and
DOS filters with standard input and standard output.

Chapter 7 gives a detailed description of DOS
commands, listed in alphabetic order. The descriptions
define the purpose, format, and type (internal or
external) of each command. Examples are given where
appropriate.

Chapter 8 describes how to use EDLIN, the line editor
to create, alter, and display source language files and
text files.

Chapter 9 describes the use of the Linker program to
link programs together before execution.

Chapter 10 tells you how to use the DEBUG program.

Appendix A explains general and device error messages
and gives an appropriate response for each message.

Contents

Chapter 1. Introduction 1-1

About Your DOS Books and Diskettes 1-3

Using Your DOS Diskettes 1-3

DOS 3.10 Features 1-4

New Commands 1-4

Enhanced Commands 1-5

About Diskette Drives and Diskettes 1-6

Types of Diskette Drives 1-6

Types of Diskettes 1-6

Diskette and Drive Compatibility 1-7

About Messages 1-8

Chapter 2. File Specification 2-1

Introduction 2-3

The File Specification 2-3

DOS Device Names 2-5

Global Filename Characters 2-7

The ? Character 2-7

The * Character 2-8

Examples of Ways to Use ? and * 2-9

Chapter 3. Preparing Your Fixed Disk 3-1

Introduction 3-3

Replacing a Previous Version of DOS 3-3

Referring to Disk Drives 3-4

Dividing Your Fixed Disk 3-4

Using FDISK 3-6

Starting FDISK 3-7

Creating a DOS Partition (Choice 1) 3-9

Using an Entire Fixed Disk for DOS . 3-10

Using Part of a Fixed Disk for DOS . . 3-11

Changing the Active Partition (Choice 2) . 3-13

Deleting a DOS Partition (Choice 3) 3-15

Displaying Partition Information (Choice 4) 3-17
Select the Next Fixed Disk Drive (Choice 5) 3-18

Formatting Your DOS Partition 3-18

Copying DOS to Your DOS Partition 3-22

Starting DOS from Your Fixed Disk 3-23

Chapter 4. Configuring Your System 4-1

Introduction 4-3

What is a Configuration File ? 4-4

Creating a CONFIG.SYS File 4-4

Configuration Commands 4-5

BREAK Command 4-6

BUFFERS Command 4-7

COUNTRY Command 4-11

DEVICE Command 4-13

Loading Standard Device Drivers .... 4-13
Installing Your Own Device Driver ... 4-13

ANSI.SYS 4-14

VDISK.SYS 4-14

FCBS (File Control Block) Command 4-19

With File Sharing 4-20

Without File Sharing 4-20

FILES Command 4-22

LASTDRIVE Command 4-24

SHELL Command 4-25

Chapter 5. Using Tree-Structured Directories .... 5-1

Introduction 5-3

Why Use Directories? 5-3

How Directories Are Organized 5-4

Directory Entries 5-5

Accessing Your Subdirectories 5-6

The Current Directory 5-6

Changing Directories with CHDIR .... 5-7

Specifying a Path to a File 5-7

Using the PATH Command 5-8

Using PATH in a Batch File 5-9

Using Directory Commands 5-10

Making a Subdirectory 5-11

Removing a Subdirectory 5-13

Displaying and Changing the Current

Directory 5-14

Displaying the Directory Structure ... 5-15
Where DOS Looks for Commands and Batch
Files 5-15

Chapter 6. Standard Input and Standard Output . . . 6-1

vui

Introduction 6-3

Redirection of Standard Input and Output

Devices 6-3

Piping of Standard Input and Output 6-6

DOS Filters 6-7

Chapter 7. DOS Commands 7-1

Introduction 7-5

DOS Commands and the Network 7-7

Types of DOS Commands 7-8

Entering a DOS Command 7-9

Information Common to All DOS

Commands 7-10

DOS Commands 7-13

ASSIGN (Drive) Command 7-14

ATTRIB (Attribute) Command 7-17

BACKUP Command 7-19

Batch File Commands 7-24

Creating a Batch File 7-26

Executing a Batch file 7-27

The AUTOEXEC.BAT File 7-27

Creating an AUTOEXEC.BAT file . . 7-28
Creating a Batch File with Replaceable

Parameters 7-28

Executing a Batch File with Replaceable

Parameters 7-29

ECHO Subcommand 7-30

FOR Subcommand 7-32

GOTO Subcommand 7-33

IF Subcommand 7-34

PAUSE Subcommand 7-38

REM (Remark) Subcommand 7-39

SHIFT Subcommand 7-40

BREAK (Control Break) Command 7-43

CHDIR (Change Directory) Command . . . 7-45

CHKDSK (Check Disk) Command 7-48

CLS (Clear Screen) Command 7-52

COMMAND (Secondary Command

Processor) Command 7-53

COMP (Compare Files) Command 7-55

COPY Command 7-60

CTTY (Change Console) Command 7-72

DATE Command 7-74

DEL (Delete) Command 7-77

DIR (Directory) Command 7-79

DISKCOMP (Compare Diskettes Only)
Command 7-84

DISKCOMP Compatibility 7-88

DISKCOPY (Copy Diskettes Only)

Command 7-90

DISKCOPY Compatibility 7-94

ERASE Command 7-96

EXE2BIN Command 7-98

FDISK Command 7-101

FIND Filter Command 7-102

FORMAT Command . 7-105

FORMAT Compatibility 7-110

GRAFT ABL (Load Graphics Table)

Command 7-113

GRAPHICS (Screen Print) Command ... 7-115
JOIN Command 7-118

Why Use JOIN? 7-122

KEYBxx (Load Keyboard) Command ... 7-123

LABEL (Volume Label) Command 7-127

MKDIR (Make Directory) Command ... 7-130

MODE Command 7-132

MORE Filter Command 7-139

PATH (Set Search Directory) Command . 7-140

PRINT Command 7-143

PROMPT (Set System Prompt) Command 7-149

RECOVER Command 7-153

RENAME (or REN) Command 7-156

RESTORE Command 7-157

RMDIR (Remove Directory) Command . 7-161

SELECT Command 7-162

SET (Set Environment) Command 7-164

SHARE Command 7-167

SORT Filter Command 7-169

SUBST(Substitute) Command 7-172

SYS (System) Command 7-178

TIME Command 7-180

TREE Command 7-182

TYPE Command 7-185

VER (Version) Command 7-186

VERIFY Command 7-187

VOL (Volume) Command 7-188

Chapter 8. The Line Editor (EDLIN) 8-1

Introduction 8-3

How to Start the EDLIN Program 8-5

Editing an Existing File 8-5

Editing a New File 8-6

The EDLIN Command Parameters 8-7

The EDLIN Commands 8-9

Information Common to All EDLIN

Commands 8-9

A (Append Lines) Command 8-11

C (Copy Lines) Command 8-12

D (Delete Lines) Command 8-13

Edit Line Command 8-16

E (End Edit) Command 8-18

I (Insert Lines) Command 8-19

L (List Lines) Command 8-22

M (Move Lines) Command 8-25

P (Page) Command 8-26

Q (Quit Edit) Command 8-27

R (Replace Text) Command 8-28

S (Search Text) Command 8-31

T (Transfer Lines) Command 8-34

W (Write Lines) Command 8-35

Chapter 9. The Linker (LINK) Program 9-1

Introduction 9-3

Files 9-4

Input Files 9-4

Output Files 9-5

VM.TMP (Temporary File) 9-5

Definitions 9-6

Segment 9-6

Group 9-7

Class 9-7

Command Prompts 9-7

Detailed Descriptions of the Command

Prompts 9-9

Object Modules [.OBJ]: 9-9

Run File [filename.EXE]: 9-10

List File [NUL.MAP]: 9-10

Libraries [.LIB]: 9-12

Linker Parameters 9-14

How to Start the Linker Program 9-17

Before You Begin 9-17

Option 1 - Console Responses 9-17

Option 2 - Command Line 9-18

Option 3 - Automatic Responses .... 9-21

Example Linker Session 9-23

How to Determine the Absolute

Address of a Segment 9-26

Messages 9-27

Chapter 10. DEBUG Program 10-1

Introduction 10-3

How to Start the DEBUG Program 10-4

The DEBUG Command Parameters 10-6

The DEBUG Commands 10-13

Information Common to All DEBUG

Commands 10-13

A (Assemble) Command 10-15

C (Compare) Command 10-19

D (Dump) Command 10-20

E (Enter) Command 10-23

F (Fill) Command 10-26

G (Go) Command 10-27

H (Hexarithmetic) Command 10-30

I (Input) Command 10-31

L (Load) Command 10-32

M (Move) Command 10-35

N (Name) Command 10-36

O (Output) Command 10-38

P (Proceed) Command 10-39

Q (Quit) Command 10-40

R (Register) Command 10-41

S (Search) Command 10-46

T (Trace) Command 10-47

U (Unassemble) Command 10-49

W (Write) Command 10-52

Appendix A. Messages A-3

Introduction A-3

Responses A-3

Device Error Messages A-4

Other Messages A-l 1

Index Index- 1

Chapter 1. Introduction

Contents

About Your DOS Books and Diskettes 1-3

Using Your DOS Diskettes 1-3

DOS 3.10 Features 1-4

New Commands 1-4

Enhanced Commands 1-5

About Diskette Drives and Diskettes 1-6

Types of Diskette Drives 1-6

Types of Diskettes 1-6

Diskette and Drive Compatibility 1-7

About Messages 1-8

1-1

Notes:

1-2

About Your DOS Books and Diskettes

DOS Version 3.10 comes with three books:

• Application Setup Guide

• DOS User's Guide

• DOS Reference

DOS also comes on two diskettes. Both diskettes are in
the back of the DOS Reference in a plastic pocket. The
first diskette, labeled "DOS," contains the DOS
programs and commands. In this book, the first
diskette is referred to as the DOS diskette. The second
diskette, labeled "DOS Supplemental Programs,"
contains the LINK Utility, EXE2BIN, a sample device
driver listing, and BASIC sample programs. In this
book, the second diskette is referred to as the
Supplemental diskette.

Using Your DOS Diskettes

DOS Version 3.10 is different from previous versions
of DOS. When you load DOS for the first time, you
need to select the keyboard layout you want to use and
the country whose date and time format you want to
use. You can select the keyboard layout and the date
and time format by using:

• The SELECT command described in Chapter 7

• The COUNTRY configuration command (Chapter
4) and the KEYBxx command (Chapter 7)

1-3

DOS 3.10 Features

This section describes the new and changed features of
DOS Version 3.10. These are the new and changed
features since DOS Version 3.00.

New Commands

The following new commands have been added to DOS
Version 3.10. Refer to the command description in
Chapter 7 of this book for further details and examples.

JOIN

Using JOIN, you can connect a drive to a directory on
another drive to create a new directory structure. You
can then access files on more than one drive using only
one drive specifier.

SUBST

Use SUBST to substitute a drive letter for a drive or a
directory. Then you can access files on that drive or
directory by referring to the drive letter. SUBST is a
way to reassign drives that is preferred over the
ASSIGN command.

If you use applications that do not recognize paths or
tree-structured directories, SUBST allows you to
substitute a drive letter for a path.

Network Support

DOS Version 3.10 supports the IBM PC Network.
You can use most DOS commands on a network disk,
directory or printer.

1-4

Enhanced Commands

The following commands have been enhanced for DOS
Version 3.10. Please refer to the command descriptions
in Chapter 7 of this book for further details.

LABEL

The LABEL command now prompts you before
deleting a volume label.

TREE

The TREE command now displays all files under the
root directory when you specify the /F parameter.

Enhanced Linker

A new parameter (/X) is available with the Linker so
that you can specify an increased number of segments.

1-5

About Diskette Drives and Diskettes

Types of Diskette Drives

Your IBM Personal Computer can have the following
types of diskette drives:

• Single sided ( 1 60KB/ 1 80KB)

. Double sided (320KB/360KB)

High capacity ( 1 .2MB)

Types of Diskettes

You can use the following types of diskettes to read and
write information:

. Single sided ( 1 60KB/ 1 80KB)

. Double sided (320KB/360KB)

High capacity ( 1 .2MB)

A Single-sided diskette contains 40 tracks, 8/9 sectors
per track, and holds up to 160K/180K bytes of
information (K equals 1024).

A Double-sided diskette contains 40 tracks, 8/9 sectors
per track, and holds up to 320K/360K bytes of
information (K equals 1024).

A High-capacity diskette is a double-sided diskette that
contains 80 tracks, 15 sectors per track, and holds up to
1.2M bytes of information (M equals 1,048,576).

1-6

Diskette and Drive Compatibility

Some combinations for reading and writing between
different diskette and drive types are not allowed. The
following sections describe which diskette and drive
combinations are allowed.

Single-Sided Drives

You can read and write to:

• Single-sided diskettes
Double-Sided Drives

You can read and write to:

• Single-sided diskettes

• Double-sided diskettes
High-Capacity Drives

You can read and write to:

• Single-sided diskettes*

• Double-sided diskettes*

• High-capacity diskettes

♦Important: If you write on any of these diskette types
using a high-capacity drive, you may not be able to read
the diskettes in a single- or double-sided drive.

You need to consider diskette and drive compatibility
when you use DOS commands that read and write to
diskettes. For example, the FORMAT command
contains a section called "FORMAT Compatibility."
Read the sections about compatibility before using the
command.

1-7

About Messages

You may get messages on your screen when you use
DOS commands. If you get a message and need help,
refer to "Messages" in Appendix A for the explanation
of the message and the action you should take.

1-8

Chapter 2. File Specification

Contents

Introduction 2-3

The File Specification 2-3

DOS Device Names 2-5

Global Filename Characters 2-7

The ? Character 2-7

The * Character 2-8

Examples of Ways to Use ? and * 2-9

Example 1 2-9

Example 2 2-9

Example 3 2-9

2-1

Notes:

2-2

Introduction

This chapter describes the file specification. It includes
a description of the drive specifier, the filename, and
the extension. It also contains information on the
acceptable filename characters, reserved device names,
and global filename characters.

The File Specification

The file specification tells DOS where to search for the
specified file. Afilespec consists of three parts: the
drive specifier, the filename, and the filename
extension. The following table describes each part of a
filespec.

Parameter

Definition

Denotes the drive specifier. It specifies the
drive that contains the file you want to refer to.
To specify the drive, type the drive letter
followed by a colon. For example, A: is the
drive specifier that represents drive A. If you
omit the drive specifier, DOS assumes the file is
located in the default drive.

2-3

Parameter

Definition

filename

Denotes the filename. The filename consists of
one to eight characters. When you type a
filename, DOS checks for invalid characters.
The following characters are invalid in
filenames.

. " / \ C 1 :
!<> + = ;,

ASCII characters less than 20H

Any other characters are valid.

ext

Denotes the filename extension. The filename
extension consists of a period followed by one
to three characters. The following characters
are invalid in a filename extension:

. " / \ [ ] :

!<> + = ;,

ASCII characters less than 20H

Any other characters are valid.

2-4

DOS Device Names

Certain names have special meaning to DOS. They are
called DOS device names. Since they are reserved, do
not name files with a DOS device name. DOS reserves
the following names:

Reserved
Name

Device

CON

Console keyboard/screen. If used as an
input device, you can press the F6 key;
then press Enter to generate an
end-of-file indication, which ends CON
as an input device.

AUX

COMl

First Serial/Parallel Adapter port.

COM2

Second Serial/ Parallel Adapter port.

LPTl

PRN

First Parallel Printer (as an output device
only).

LPT2

and

LPT3

Second Parallel Printer
Third Parallel Printer

NUL

Nonexistent (dummy) device for testing
applications. As an input device,
immediate end-of-file is generated. As
an output device, the write operations are
simulated, but no data is actually written.

2-5

Notes:

1. Since these are reserved names, you cannot create
files with these names.

2. When using a device name, you should assure that
the device actually exists. Using the name of a
nonexistent device can cause unpredictable errors
in DOS operation.

3. The reserved device names can be used in place of
a filename in DOS commands.

4. The colon after the device name is optional. For
example, you can type:

CON

CON:

2-6

Global Filename Characters

Two special characters ? and * can be used within a
filename and its extension. These special characters
give you greater flexibility with the DOS commands.

The ? Character

A ? in a filename or in a filename extension indicates
that any character can occupy that position. For
example,

A>dir ab?de.xyz

lists all directory entries on the default drive with
filenames that have five characters, begin with AB,
have any next character, are followed by DE, and have
an extension of XYZ.

Here are some examples of the files that might be listed
by the DIR command:

ABCED XYZ
ABIDE XYZ
ABODE XYZ

2-7

The * Character

An * in a filename or in a filename extension indicates
that any character can occupy that position and all the
remaining positions in the filename or extension. For
example,

A>dir ab*.xyz

lists all directory entries on the default drive with
filenames that begin with AB and have an extension of
XYZ. In this case, the filenames may be from 2 to 8
characters in length.

Here are some example files that might be listed by the
DIR command:

ABCDE

XYZ

ABC357

XYZ

ABIDE

XYZ

ABIIOU

XYZ

AB0$$$

XYZ

2-8

Examples of Ways to Use ? and *
Example 1

To list the directory entries for all files named INPUT
on drive A (regardless of their filename extension),
type:

A>dir an'nput.???

or
A>dir a:input.*

Example 2

To list the directory entries for all files in the current
directory on drive A (regardless of their filenames) with
a filename extension of XYZ, type:

A>dir a:????????.xyz

or
A>dir a:*.xyz

Example 3

To list the directory entries for all files on drive A with
filenames beginning with ABC and extensions
beginning with E, type:

A>dir a:abc?????.e??

or
A>dir a:abc*.e*

2-9

Notes:

2-10

Chapter 3. Preparing Your Fixed Disk

Contents

Introduction 3-3

Replacing a Previous Version of DOS 3-3

Referring to Disk Drives 3-4

Dividing Your Fixed Disk 3-4

Using FDISK 3-6

Starting FDISK 3-7

Creating a DOS Partition (Choice 1) 3-9

Using an Entire Fixed Disk for DOS 3-10

Using Part of a Fixed Disk for DOS 3-11

Changing the Active Partition (Choice 2) 3-13

Deleting a DOS Partition (Choice 3) 3-15

Displaying Partition Information (Choice 4) 3-17

Select the Next Fixed Disk Drive (Choice 5) 3-18

Formatting Your DOS Partition 3-18

Copying DOS to Your DOS Partition 3-22

Starting DOS from Your Fixed Disk 3-23

3-1

Notes:

3-2

Introduction

If your IBM Personal Computer has a fixed disk, you
must prepare the fixed disk before DOS can use it.

This chapter tells you how to:

Refer to your computer's disk drives

Use FDISK to prepare your fixed disk for DOS

Replace a previous version of DOS on your fixed
disk with DOS 3.10

Format your fixed disk

Copy DOS to your fixed disk

Start DOS from your fixed disk

Do other tasks with FDISK

Replacing a Previous Version of DOS

If you already have a version of DOS on your fixed disk
prior to DOS 3.10, follow these steps to replace it with
DOS 3.10:

Note: If you have not prepared your fixed disk
with a previous version of DOS, skip this section.
Go to "Referring to Disk Drives."

1. Insert your DOS 3.10 diskette in the diskette
drive.

2. Press Ctrl-Alt-Del.

3. At the DOS prompt, type:

sys c: (Press Enter)

3-3

If you have more than one fixed disk, be sure to
type the drive letter for the fixed disk on which you
want to place DOS 3.10.

4. Copy the rest of the DOS files to your fixed disk.
Type:

copy *.* c: (Press Enter)

5. Repeat step 4 with your Supplemental DOS
diskette.

Now your fixed disk is ready to be used with DOS 3.10.
For information about starting DOS see the section in
this chapter entitled, "Starting DOS from Your Fixed
Disk."

Referring to Disk Drives

DOS assigns drive letters to the diskette drives and to
the fixed disk on your computer.

For example, if your computer has one diskette drive
and one fixed disk drive, DOS assigns the drive letters
A and B to the diskette drive and the letter C to the
fixed disk. If your computer has two diskette drives
and two fixed disk drives, the diskette drives are A and
B, and the fixed disks are C and D. You can install a
third fixed disk, to which DOS assigns the drive letter
E.

Dividing Your Fixed Disk

You can divide a fixed disk into one, two, three or four
sections called partitions. Partitions separate fixed disk
space into individual areas. To prepare your fixed disk

3-4

for DOS, you create a partition for DOS called a DOS
partition. To do this, you will use the fixed disk setup
program supplied by DOS called FDISK.

If you are using more than one operating system, you
need a separate partition for each operating system. If
DOS is your only operating system, you only need one
partition.

3-5

Using FDISK

With the FDISK program, you can create a DOS
partition and do other fixed disk tasks.

FDISK allows you to:

Create a DOS partition

Change an active partition

Delete a DOS partition

Display partition data

Select the next fixed disk drive for partitioning if
you have more than one.

FDISK has menus and screens that guide you through
the tasks. To find out how to use FDISK, continue
with "Starting FDISK."

3-6

Starting FDISK

To start FDISK, follow these steps:

1. With your DOS diskette in drive A, at the DOS
prompt A>, type:

A>fdisk

2. Press Enter.

The FDISK Options menu appears. Choose what
you want to do. If you make a mistake or change
your mind, press Esc to return to the FDISK
Options menu. After making a selection, you see a
series of screens.

IBM Personal Computer

Fixed Disk Setup Program Version 3.10

(C)Copyright IBM Corp. 1983,1984

FDISK Options

Current

Fixed Disk Drive: 1

Choose

one of the following:

2.
3.
4.
5.

Create DOS Partition
Change Active Partition
Delete DOS Partition
Display Partition Data
Select Next Fixed Disk Drive

Enter

choice: [1]

Press

ESC to return to DOS

3-7

Each screen displays a default choice value. If you
want the default value as your choice, press Enter.
If you want a different value than the default
value, type the value you want, then press Enter.

Choices 1 through 4 appear if your computer has
one fixed disk attached. Choice 5 appears if your
computer has more than one fixed disk attached.
When you first see this menu, the Enter choice
field will have a 1 in it.

3. Do one of the following:

• If you want to increase a DOS partition, go to
"Creating a DOS Partition."

• If you want to change an active partition, go
to "Changing the Active Partition."

• If you want to delete a DOS partition, go to
"Deleting a DOS partition."

• If you want to display information about the
partitions on your fixed disk, go to
"Displaying Partition Information."

• If you want to use FDISK on another fixed
disk drive, go to "Select the Next Fixed Disk
Drive."

3-8

Creating a DOS Partition (Choice 1)

Do one of the following:

• If DOS is the only operating system that you
intend to use with your fixed disk, follow the
instructions in the section "Using an Entire Fixed
Disk for DOS."

• If you intend to use part of the fixed disk with
another operating system, follow the instructions
for "Using Part of a Fixed Disk for DOS."

Choice 1 (Create a DOS partition) is the default value
for the FDISK Options menu. To create a DOS
partition, press Enter. The following screen appears:

Create DOS Partition
Current Fixed Disk Drive: 1

Do you wish to use the entire fixed disk
for DOS (Y/N) ? [Y]

3-9

Using an Entire Fixed Disk for DOS

The following message appears if you told the computer
you wanted to use an entire fixed disk for DOS:

System wil 1
Insert DOS
Press any k

now restart
diskette in drive
ey when ready . .

1 . Insert your DOS diskette in drive A and press any
key.

DOS restarts and prompts you to enter the date
and time.

2. Enter the date.

3. Enter the time.

When you see the DOS prompt, the DOS partition
has been created. Before you can use the DOS
partition, you must format the disk.

4. Go to "Formatting Your DOS Partition" later in
this chapter to continue.

3-10

Using Part of a Fixed Disk for DOS

The following message appears if you told the computer
you wanted to use only part of a fixed disk for DOS:

Total fixed disk space is xxxx cylinders
Maximum available space is xxxx
cylinders at xxxx.

"Total fixed disk space" tells you how many cylinders
you have on your entire disk. "Maximum available
space" tells you how many cylinders are left for you to
partition. The following prompt appears:

Enter partition size : [xxxx]

1. Do one of the following:

• If you want your DOS partition to use all the
available space, press Enter.

• If you do not want to use all the available
space for DOS, type the size you want to use
(in cylinders).

The following prompt appears:

Enter starting cylinder number. .: [xxxx]

3-11

2. The starting cylinder number you see depends on
the partition size you specified. If you want the
DOS partition to be located there, press Enter. If
not, type the starting cylinder number you want
and press Enter.

3. The DOS partition is created, but before you can
use it, you must:

• Change the active partition (FDISK Options
menu Choice 2).

• Format your DOS partition (refer to
"Formatting Your DOS Partition" later in this
chapter).

4. If there are bad spots at the start of the specified
partition, FDISK automatically adjusts the start of
the partition to the first good area on the disk that
it finds. This may decrease the size of the
partition.

3-12

Changing the Active Partition (Choice 2)

Your fixed disk can have many partitions, but only one
partition can be active. The active partition is the one
that gets control of your computer when you turn it on
or reset the computer. Only one partition can be active
at a time. If DOS is the active partition, DOS controls
the computer when it is turned on or reset.

If you type 2 on the FDISK Options menu, a screen like
the one shown here appears. This sample screen shows
the partition status of a fixed disk that has three
partitions.

Change Act

ive Partition

Current Fixed Dis

k Drive:

Partition
1
2

Status
A
N

Type

DOS

non-DOS

Start
000
150

End
149
304

Size
150
155

XXX

Total disk

space

i s 305

cylinders

Enter the
want to ma

number of the partition you
ke active : [ ]

3-13

Partition

The number assigned to the partition.

Status

The status of the partition — A for
active, N for non-active.

Type

The kind of partition — DOS or
non-DOS.

Start/End

The starting and ending cylinder
numbers of the partition.

Size

The number of cylinders the partition
uses.

Do the following:

1 . Type the number of the partition that you want to
be active. (If you want your DOS partition to be
active, type the number for the DOS partition.)

2. Press Enter. The partition you selected then
becomes the active partition.

3. Go to "Starting DOS from Your Fixed Disk."

3-14

Deleting a DOS Partition (Choice 3)

You can delete the fixed disk partition you use for
DOS. When you do, remember any data in that
partition is also deleted and cannot be recovered. The
boundaries for that partition are also removed.

Note: If you delete the DOS partition but want to
continue using DOS, insert a DOS diskette in drive
A and start DOS again.

1 . If you typed 3 on the FDISK Options menu, you
will see a screen like the one shown here.

Delete DOS Partition

Current Fixed Dis

k Drive:

Partition Status

Type

Start

End

Size

1 N

DOS

000

304

305

Total fixed disk

space is

305

cyl ir

ders

Warning! Data in

the DOS

partition

will be lost. Do

you wis

h to

continue

CN]

When the screen first appears, you will see an N
(no) next to the prompt "Do you wish to
continue?"

3-15

2. Do one of the following:

• If you do not want to delete the DOS
partition, press Enter to return to the FDISK
Options menu.

• If you want to delete the DOS partition, type y
(yes) and press Enter.

You need to start another operating system
from the fixed disk or restart DOS from a
diskette to proceed.

3-16

Displaying Partition Information
(Choice 4)

You can display information that tells how a fixed disk
on your computer is partitioned.

If you typed 4 on the Fixed Disk Options menu, you
will see a screen like the one shown here.

Display Partition Information
Current Fixed Disk Drive: 1

Partition Status Type Start End Size

1 A DOS 000 199 200

2 N non-DOS 200 304 105

Total fixed disk space is 305 cylinders

You see the:

Partition number
Partition status
Partition type
Starting cylinder number
Ending cylinder number
Size in cylinders

3-17

Select the Next Fixed Disk Drive
(Choice 5)

If your computer has more than one fixed disk attached,
you can use the same FDISK menu options for each
one. If you type 5 on the FDISK Options menu, you
can prepare another fixed disk.

Formatting Your DOS Partition

Formatting your DOS partition is the final step in
preparing it for DOS use. You should format a DOS
partition the first time you create it or if you want to
erase all of the data contained in the DOS partition.

Note: If your DOS partition is larger than 10M
bytes and you format it using DOS Version 3.10,
you cannot use versions of DOS prior to DOS 3.00
to access your fixed disk.

3-18

You use the DOS FORMAT command to format your
DOS partition.

Follow these steps to format your DOS partition on
drive C:

1 . With your DOS diskette in drive A, at the DOS
prompt A>, type:

A>format c:/s/v

2. Press Enter.

The following appears on the screen:

Warning, All data on Non-removable
Disk drive C: Will be lost!
Proceed with Format (Y/N)?

Warning: FORMAT destroys any data contained in
your DOS partition. Be sure you wish to format
the contents of your DOS partition disk before you
continue.

3-19

Type y, then press Enter. The "In-Use" light on
your fixed disk comes on and the message
Formatting... is displayed. It takes several minutes
to format your fixed disk so do not worry.

Next you will see:

Formatting... Format complete

System transferred

Volume label (11 characters, ENTER for none)?

The message "System transferred" is displayed
because you specified the /S parameter. It means
that a copy of the operating system files
IBMBIO.COM, IBMDOS.COM, and
COMMAND.COM has been placed in the DOS
partition.

4. You are asked to enter a volume label consisting of
up to 11 characters (for example
MYFIXEDDISK).

Note: Characters that are valid for filenames
are also valid for volume labels. Refer to
Chapter 2 "The File Specification" for
information on filename characters.

The volume label is used to identify the fixed disk.

5. Do one of the following:

• If you want to label your fixed disk, type a
name and press Enter.

• If you do not want to label your fixed disk,
press Enter.

3-20

Note: You can add or change the volume
label by using the LABEL command. Refer
to Chapter 7 "DOS Commands" for more
information.

After you have answered the volume label prompt,
disk space statistics are displayed along with the
DOS prompt A>. Now, your DOS partition is
formatted and ready to be used by DOS.

If you want to copy the remaining DOS files from
the DOS diskette, refer to the next section,
"Copying DOS to Your DOS Partition."
Otherwise, skip the next section and go to
"Starting DOS from Your Fixed Disk" at the end
of this chapter.

3-21

Copying DOS to Your DOS Partition

You can also copy the external DOS commands from
the DOS diskette and the Supplemental diskette into
the DOS partition. Use the COPY command:

COPY d:** d:

Note:

For more information on the COPY command,
refer to Chapter 7 "DOS Commands."

Follow these steps to copy DOS to your DOS partition
on drive C:

1. With your DOS diskette in drive A, at the DOS
prompt A>, type:

A>copy a:*.* c:

2. Press Enter.

3. To copy the commands from the Supplemental
diskette, remove the DOS diskette from drive A
and insert your Supplemental diskette. Type:

A>copy a:*.* c:

4. Press Enter.

5. Go to "Starting DOS from Your Fixed Disk."

Now you can run all of the DOS commands from the
fixed disk. You should store your DOS diskettes in a
safe place.

3-22

Starting DOS from Your Fixed Disk

Starting DOS from your fixed disk means that when
you switch on the power or do a system reset (restart
DOS), DOS is loaded from the DOS Partition. DOS
can only be loaded from the first fixed disk drive
attached to your computer.

1. To start DOS from your fixed disk, make sure that:

• You leave the drive door for Drive A open
when you switch on the power or perform a
system reset.

• You have placed a copy of the operating
system files in the DOS partition.

• You have partitioned your entire disk for DOS
or you have made the DOS partition the active
partition.

2. Do one of the following:

• If your computer is off, switch on your
computer.

• If your computer is on, press Ctrl-Alt-Del
(system reset).

After you have set up your fixed disk, you may
want to refer to Section 5, "Using Directories," for
information on how to organize your files.

3-23

Notes:

3-24

Chapter 4. Configuring Your System

Contents

Introduction 4-3

What is a Configuration File ? 4-4

Creating a CONFIG.SYS File 4-4

Configuration Commands 4-5

BREAK Command 4-6

BUFFERS Command 4-7

What Is a Buffer ? 4-7

Read/Write Requests 4-8

Random/ Sequential Applications 4-8

Size of Your Computer 4-9

COUNTRY Command 4-11

DEVICE Command 4-13

Loading Standard Device Drivers 4-13

Installing Your Own Device Driver 4-13

ANSI.SYS 4-14

VDISK.SYS 4-14

Installing VDISK 4-15

FCBS (File Control Block) Command 4-19

With File Sharing 4-20

Without File Sharing 4-20

FILES Command 4-22

Accessing a File 4-22

Number of Files Opened 4-22

LASTDRIVE Command 4-24

SHELL Command 4-25

4-1

Notes:

4-2

Introduction

This chapter describes how to configure your system by
creating a file named CONFIG.SYS. A list of the
configuration commands is given with a description of
the purpose and format of the command. You can use
configuration commands to:

Set extended checking of Ctrl-Break (BREAK)

Specify the number of disk buffers (BUFFERS)

Specify the country whose date and time format
you want to use (COUNTRY)

Install device drivers (DEVICE)

Specify the number of files that can be opened by
file control blocks (FCBS)

Specify the number of files that can be open at one
time (FILES)

Set the maximum drive letter that you may access
(LASTDRIVE)

Specify the name of a top-level command
processor (SHELL)

4-3

What is a Configuration File ?

A configuration file contains commands that are used
to configure your system. Each time you start DOS,
DOS searches the root directory of the drive it was
started from for the file named CONFIG.SYS. If the
file CONFIG.SYS is found, DOS reads the file and
interprets the commands within the file. If the file
CONFIG.SYS is not found, DOS assigns default values
for the configuration commands.

Create a configuration file named CONFIG.SYS to
change the default values of the configuration
commands. If you add or change any of the
configuration file commands, the changes are not in
effect until the next time you start DOS.

Creating a CONFIG.SYS File

Create a CONFIG.SYS file using an editor (such as
EDLIN) or the DOS COPY command. This section
describes how to create a CONFIG.SYS file using the
COPY command directly from the standard input
device.

Note: If you have used the SELECT command, a
CONFIG.SYS file has already been created that
includes the the COUNTRY configuration
command. You should use EDLIN or an editor to
add other configuration commands.

4-4

Follow these steps to create a CONFIG.SYS file using
the COPY command.

1. At the DOS prompt A>, type:

A>copy con config.sys

2. Press Enter.

3. Type the configuration commands you want in the
CONFIG.SYS file. Press Enter after you type
each command.

4. When you have finished typing the commands,
press the F6 key and then Enter. This ends the
COPY CON command and saves the file.

Now a file named CONFIG.SYS has been created. But
the values for the commands are not in effect until the
next time you start DOS.

Configuration Commands

The following section describes the commands that you
can include in a CONFIG.SYS file.

4-5

BREAK

Command

Purpose: Allows you to instruct DOS to check for control

break whenever a program requests DOS to perform
any functions.

Format: BREAK = [ON | OFF]

Remarks: The default value is set at BREAK = OFF. This
means that DOS will only check for Ctrl-Break
being entered during:

• Standard output operations

• Standard input operations

• Standard print operations

• Standard auxiliary operations

If you want DOS to check for Ctrl-Break whenever
it is requested, set BREAK = ON. This allows you
to break-out of a program that produces few or no
standard device operations (such as a compiler). For
instance, if a program is being compiled, it is
important to have a way to stop compilation if an
error or loop is encountered.

4-6

BUFFERS

Command

Purpose: Allows you to determine the number of disk buffers
that DOS will allocate in memory when it starts.

Format: BUFFERS = x

Remarks: The x is a number between 1 and 99. This is the
number of disk buffers that DOS allocates in
memory when it starts. The default value is 2, (3 for
the IBM Personal Computer AT) and this value
remains in effect until DOS is restarted with a
different value specified in the configuration file.

What Is a Buffer ?

A disk buffer is a block of memory that DOS uses to
hold data being read from, or written to a disk. For
example, if an application reads a 128-byte record
from a file, DOS reads the entire sector into one of
its buffers, locates the correct 128-byte record in the
buffer, and moves the record from the buffer into the
application's area of memory. It then marks that
buffer as having been used recently. On the next
request to transfer data, DOS attempts to use a
different buffer. In this way, all of the buffers
eventually contain the most recently-used data. The
more buffers DOS has, the more data is in memory.

4-7

BUFFERS

Command

Read/Write Requests

Before DOS reads or writes a record that is not an
exact multiple of the sector size, it checks to see if
the sector containing that record is already in a
buffer. If not, it must read the sector as described
above. But if the data is already in a buffer, DOS
can simply transfer the record to the application's
area without reading the sector from the disk. This
saves time, both in reading and writing records,
because DOS must first read a sector before it can
insert a record that your application is attempting to
write.

Random/Sequential Applications

For applications that read and write records in a
random fashion (such as many BASIC and data base
applications), the likelihood of finding the correct
record already in a buffer increases if DOS has more
buffers to work with. This can increase performance
of those applications by speeding up the access time.

For applications doing sequential reads and writes,
however (read an entire file, write an entire file),
there is little advantage to having a large number of
buffers allocated.

Because all applications are different, there is no
specific number of buffers that will serve all
applications equally well. If your applications do
little random reading and writing of records, the
system default of two buffers should be sufficient.

4-8

BUFFERS

Command

However, if you use data base type applications, or
run programs that perform a lot of random reads and
writes of records, you will want to increase the
number of DOS buffers. The "best" number of
buffers for your particular application can only be
determined by using different values until the desired
performance is achieved. For most data base
applications, a value between 10 and 20 buffers
usually provides the best results. For subdirectories,
between 10 and 25 buffers usually provides desirable
performance.

Beyond that point, the system may appear to start
running slower. With a very large number of buffers,
it can take DOS longer to search all the buffers for a
record than it would take to read the record from
disk.

Size of Your Computer

The final consideration in determining the number of
buffers to allocate is the memory size of your
computer. Since each additional buffer increases the
resident size of DOS by 528 bytes, the amount of
memory available to the application is reduced by
that amount. Additional buffers may actually cause
some applications to run more slowly because there
is less memory available for the application to keep
data. This could result in more frequent reads and
writes than would otherwise be necessary.

4-9

BUFFERS

Command

In summary, the optimum number of buffers must be
determined by you, based on:

• The types of applications most often used

• The memory size of your computer

• Your analysis of system performance when
using your applications with different numbers
of buffers allocated

• For computers with fixed disks, a minimum of
BUFFERS =3 is recommended

4-10

COUNTRY
Command

Purpose: Use to specify the date and time format for a given
country. Other information, such as the currency
symbol and the decimal separator for a particular
country, are also set using the COUNTRY
command.

Note: COUNTRY does not translate the text of
DOS messages for the country you specify.

Format: COUNTRY = xxx

Remarks: xxx is the 3— digit international country code for the
telephone system. The default value is the U.S.
country code of 001. The following countries are
supported for DOS Version 3.10. If your country is
not supported, choose the most familiar country
supported.

4-11

COUNTRY
Command

Country

Country Code

United States

001

Netherlands

031

Belgium

032

France

033

Spain

034

Italy

039

Switzerland

041

United Kingdom

044

Denmark

045

Sweden

046

Norway

047

Germany

049

Australia

061

Finland

358

Israel

972

Example: To specify the date and time format for the United
States, include the following command in the
CONFIG.SYS file.

country=001

The next time you start DOS, the date format is
mm-dd-yy, the time format is hh:mm:ss, the decimal
separator is a period (.), and the currency symbol is

4-12

DEVICE

Command

Purpose: Allows you to specify the name of a file containing a
device driver.

Format: DEVICE = [d:]\path]filename[.ext]

Remarks: During startup, DOS loads the file into memory and
gives it control as described in "Installation of
Device Drivers" in Chapter 2 of DOS Technical
Reference. Please refer to that section for technical
information about installable device drivers.

Loading Standard Device Drivers

The standard device drivers loaded by DOS support
the standard input, standard output, standard printer,
diskette, and fixed disk devices. A clock driver is
also loaded (see Chapter 2 of the DOS Technical
Reference). You don't need to specify any
DEVICE = commands for DOS to support these
devices.

Installing Your Own Device Driver

For systems programmers and application
developers — if you have written device drivers that
you want DOS to load when it starts, include a
DEVICE= command in the CONFIG.SYS file for
each driver to be loaded.

You must install the device drivers that come with
DOS (ANSI.SYS, VDISK.SYS) before you can use
them.

4-13

DEVICE
Command

ANSI.SYS

To use the "Extended Screen and Keyboard
Control" features described in the DOS Technical
Reference, create the file CONFIG.SYS on the disk
you will be starting DOS from. The file should
contain the command DEVICE=ANSI.SYS. This
command causes DOS to replace the standard input
and standard output support with the extended
functions.

VDISK.SYS

The VDISK.SYS file on your DOS diskette is a
device driver that simulates a disk drive by using a
portion of your computer's memory as the storage
medium. These simulated disks are called virtual
disks. The following characteristics apply to virtual
disks:

• Virtual disks are fast, since they operate at the
speed of your computer's memory.

• You can install more than one virtual disk; each
is referred to by a drive letter, in the same way
you refer to disk drives. For example, if your
computer has two diskette drives and no fixed
disks, the diskette drives are referred to as
drives A and B, the first virtual disk is referred
to as C, the second as D, and so on.

• If you have an IBM Personal Computer AT with
extended memory installed, (starting at the 1MB
boundary), you can use the extended memory as
one or more virtual disks. Otherwise, virtual
disks are located in low memory.

4-14

DEVICE

Command

For each virtual disk, you can specify the
amount of memory to be used (the "disk size"),
the sector size, and the number of directory
entries it is to contain.

A volume label is created on each virtual disk to
assist in its identification.

Each virtual disk created increases the resident
size of DOS by 720 bytes for the VDISK.SYS
device driver plus the size of the virtual disk
buffer you specify (if the driver is installed in
low memory).

The contents of a virtual disk are lost if you
restart the system or if power is lost.

Virtual disks cannot be formatted. Each VDISK
is installed in formatted form.

Installing VDISK

To install the VDISK device driver, include this
statement in the CONFIG.SYS file:

device=[^:][p«//z]vdisk.sys [bbb][sss][ddd][/E [:ra]]

[d:][path] is the drive and directory path containing
the VDISK.SYS file.

The bbb is the virtual disk size in K bytes, and is
specified as a decimal value. The default value is
64K bytes. The range of values is between 1 and the
amount of available memory on your computer.
VDISK may adjust the amount of memory actually
used for the virtual disk as follows:

4-15

DEVICE

Command

• If there is less than 64K of available memory at
the time VDISK is being installed, VDISK issues
an error message and does not install the virtual
disk.

• If the size you specify is less than IK byte or
greater than the total amount of memory on
your computer, VDISK uses the default value of
64K.

• If the specified size leaves less than 64K of
available memory, VDISK adjusts the virtual
disk size downward (VDISK always leaves a
minimum of 64K of available memory after the
installation of the virtual disk).

The sss is the sector size in bytes. Allowable sizes
are 128, 256, or 512. If omitted, or if an incorrect
value is typed, VDISK uses the default value of 128.
If you use your virtual disk to hold relatively small
files, you may wish to use a smaller sector size to
minimize wasted space.

The ddd is the number of directory entries (number
of files) that the virtual disk can contain (one
directory entry is required for each file). The default
value is 64. The range of values is between 2 and
512. VDISK may adjust the value you entered as
follows:

• The value is adjusted upwards to the nearest
sector size boundary. For example, if you
specify a value of 10, and your sector size is
128, VDISK generates 12 directory entries (12
entries at 32 bytes each to round up to a
multiple of the sector size).

• If the virtual disk size specified above is too
small to hold the file allocation table, the

4-16

DEVICE

Command

directory, and 2 additional sectors, the directory
size is adjusted downward by 1 sector at a time
until these conditions are met. If the directory
size reaches 1 sector and the conditions still
cannot be met, VDISK issues an error message
and the virtual disk is not installed.

• VDISK uses one of the directory entries to hold
the volume label.

/E is a parameter that tells VDISK to use extended
memory. Extended memory is memory at or above
1M bytes. The virtual disk buffer will be in extended
memory and the device driver will be installed in low
memory. More than one virtual disk can be installed
in extended memory by including more than one
DEVICE= VDISK.SYS command in the
CONFIG.SYS file. The first device driver is
installed at the 1 M-byte boundary, the second
would immediately follow the first, and so on. This
parameter is only valid for an IBM Personal
Computer AT with extended memory. If you specify
this parameter for a computer that does not have
extended memory, an error message is displayed and
the virtual disk is not installed.

The following example installs a 160K-byte virtual
disk with 512-byte sectors and 64 directory entries.

device=vdisk.sys 160 512 64

The m is the maximum number of sectors (of size
sss) of data VDISK transfers at a time. The default
for m is 8. The possible values for m are 1, 2, 3, 4, 5,
6, 7, and 8. When VDISK is operating in extended
memory, interrupt servicing is suspended during
data transfers. If there are very frequent interrupts
occurring during these periods (as in high speed
communications), some interrupts can be lost.

4-17

DEVICE

Command

Note: If some interrupts are being lost, isolate
the problem in the following manner. Install
VDISK in non-extended memory. If the
problem is resolved, adjust m (in extended
memory) until no interrupts are lost. If an m of
1 and sss of 128 does not improve the situation,
then VDISK cannot be used in extended
memory in that environment. If installing
VDISK in non-extended memory does not
resolve the problem, other areas should be
investigated as the cause of the problem.

The next time you start DOS, VDISK displays the
following message:

VDISK Version 2.0 virtual disk x

This message is displayed as an informative message
to tell you that VDISK is attempting to install a
virtual disk. It also tells you the drive letter jc that is
assigned to the virtual disk.

4-18

FCBS (File Control Block)

Command

Purpose: Allows you to specify the number of file control
blocks (FCBs) that can be concurrently open by
DOS.

Format: FCBS = m,n

Remarks: The m specifies the total number of files opened by
FCBs that can be open at one time. The default
value is 4. The range of values for m is from 1 to

255.

The n specifies the number of files opened by FCBs
that cannot be closed automatically by DOS if a
program tries to have more than m files opened by
FCBs at one time. The first n files opened by FCBs
are protected from being closed. The default value is

0. The range of values for n is between and 255.

Some application programs use file control blocks to
create, open, delete, read and write to files. DOS
keeps track of the least recently used FCB. If the
program tries to open more than m FCB files, the
action DOS takes depends on whether file sharing is
loaded.

Notes:

1 . The value of m must be greater than or equal to
the value of n.

2. If a program receives critical errors due to FCB
files being closed by DOS, increasing the value
of m may prevent these errors from occurring.

4-19

FCBS (File Control Block)
Command

If a program uses two or more different FCBs to
refer to the same file, DOS only counts this as
one FCB used.

If you specify the FCBS command in your
configuration file, the resident size of DOS is
increased.

With File Sharing

If file sharing is loaded, and a program tries to open
more than m files, DOS closes the least recently used
FCB and opens the new file. Note that the first n
files are not included in the list of files that DOS
tracks for the least recently used FCB. Therefore,
they are protected from being closed this way. If a
program tries to read or write to a file that has been
closed because it is the least recently used FCB,
DOS issues the following message:

FCB unavailable
Abort, Retry, Ignore?

Note: If you set m equal to n, it does not allow
any files to be closed by DOS if a program tries
to open more than m files. If a program tries to
open more than m files, DOS does not open the
new file.

Without File Sharing

If sharing is not loaded, the number of files that can
be open at the same time is not limited. The FCBS
command is only applicable when file sharing is
loaded.

4-20

FCBS (File Control Block)

Command

Example: To set the total number of FCB files that can be
open at one time to 3, and the number protected
from being closed to 1 , include this command in the
CONFIG.SYS file.

fcbs=3,l

4-21

FILES
Command

Purpose: Allows you to specify the maximum number of file
handles that can be open concurrently.

Format: FILES = x

Remarks: The x can be a number between 8 and 255. The
default value is FILES=8.

Accessing a File

All file accesses (reads, writes, close) can be
performed by telling DOS which handle to use.
When an application opens a file in this manner,
DOS constructs a control block in its own memory
on behalf of the application, in an area that was set
aside when DOS started. The size of this area (and
consequently, the maximum number of file handles
that can be concurrently open) , depends on the value
specified in the FILES = command.

The default value is FILES=8; that is, no more than
8 file handles can be open at the same time. There is
no effect on the number of files that can be
concurrently open using the traditional (OPEN
FCB) functions. This default value is sufficient for
the majority of operating environments. However, if
applications are installed that result in error messages
indicating an insufficient number of handles, the
FILES = command should be used to provide DOS
with additional handles.

4-22

FILES

Command

Number of Files Opened

The value specified in FILES = becomes the new
maximum number of file handles that DOS allows to
be concurrently open.

Note that this value is the maximum number of
handles allowed for the entire system. This includes
handles in use by currently running foreground tasks
(programs such as COMP and CHKDSK) and
background tasks like PRINT and the network. The
maximum number of file handles that a process can
have open is 20 (this number includes the 3 used by
DOS for the 5 predefined handles for standard input,
standard output, standard error, auxiliary, and
standard printer). So the limit on handles ^or the
system is specified by FILES=, and the limifbn
handles for each process is is 20.

If you specify FILES = in your configuration file, the
size of the resident portion of DOS increases by 48
bytes for each additional file above the default value
of 8. Consequently, the memory available to the
application is reduced by the same amount. See
function calls 3CH through 46H in Chapter 5 of the
DOS Technical Reference for descriptions of the new
file-handling functions.

4-23

LASTDRIVE
Command

Purpose: Sets the maximum number of drives that you may

access.

Format: LASTDRIVE = x

Remarks: The x can be any alphabetic character A through Z.
It represents the last valid drive letter that DOS may
accept. The default value is LASTDRIVE = E.

The minimum number you can set LASTDRIVE
equal to is the number of drives you have installed on
your computer. If x is less than the number of
physical drives on the your computer, this command
is ignored in the configuration file.

Example: To set the number of drives equal to 16, include this
command in the CONFIG.SYS file:

lastdrive=p

4-24

Purpose:

SHELL
Command

Allows you to specify the name and location of a
top-level command processor that DOS initialization
loads in place of COMMAND.COM.

Format: SHELL= [d:][pa.th]filename[.ext]

Remarks: System programmers who develop their own

top-level command processor should remember to
include provisions for handling interrupts 22H, 23H
and 24H, and for reading and executing commands.
Because the internal commands and batch processor
reside in COMMAND.COM., these functions will
not be available to the user unless they are duplicated
in your command processor.

SHELL does not affect COMSPEC= or BASIC'S
SHELL command. To assure that the same
command processor is used for reloading (just the
transient portion), you must set COMSPEC= to
point to that command processor.

4-25

Notes:

4-26

Chapter 5. Using Tree-Structured
Directories

Contents

Introduction 5-3

Why Use Directories? 5-3

How Directories Are Organized 5-4

Directory Entries 5-5

Accessing Your Subdirectories 5-6

The Current Directory 5-6

Changing Directories with CHDIR 5-7

Specifying a Path to a File 5-7

Using the PATH Command 5-8

Using PATH in a Batch File 5-9

Using Directory Commands 5-10

Making a Subdirectory 5-11

Removing a Subdirectory 5-13

Displaying and Changing the Current

Directory 5-14

Displaying the Directory Structure 5-15

Where DOS Looks for Commands and Batch Files 5-15

5-1

Notes:

5-2

Introduction

This chapter describes how to organize files into
groupings called directories. It tells you how to create,
access, remove and display the contents of your
directories. It also tells you how to display the entire
directory structure of your disk.

Why Use Directories?

A fixed disk can have many files. If you keep a large
number of files in one place on your fixed disk, it can
take longer for DOS to find a particular file. Keeping
files in related groups in directories can reduce the time
required to locate a file.

5-3

How Directories Are Organized

To give you an idea of how you might group files into
directories, let's assume your company has two
departments — sales and accounting — that use an
IBM Personal Computer. All of the sales and
accounting files are kept on the computer's fixed disk.
The directory structure might look like this:

ROOTDIR

SALES

ACCTNG

LINDA

RUTH

LEE

RAE

REPORTS

PROGRAMS

REPORTS

Weekly. rep

Basic.com

5-4

This directory structure reflects the organization of
each of the two departments. Directories can be
created on different levels. The highest level is the root
directory. DOS creates a root directory on each disk
when you format it. When you start DOS on your
computer, you are in the root directory.

Just below the root directory shown in the previous
diagram, are two subdirectories — one for sales and one
for accounting. One level below the subdirectory
named SALES, you find two more subdirectories.
These two subdirectories can contain files for the
salespersons, Ruth and Linda. The complete name of
Ruth's subdirectory is actually \ SALES \ RUTH. The
complete name of Linda's subdirectory is
\ SALES \ LINDA.

Ruth and Linda can store files related to their work in
their respective subdirectories. But suppose Ruth and
Linda want to keep all files related to reports separate
from their other files. On the next level, each has a
subdirectory named REPORTS. The complete name of
each subdirectory is \ SALES \ RUTH \ REPORTS and
\ SALES \ LINDA \ REPORTS.

Note: Sales files of a general nature, not related to
a particular salesperson, can be stored in SALES.

Directory Entries

A directory entry can be a file, a subdirectory, or a
volume label. The number of entries that the root
directory of a disk can contain depends on the type of
disk. The root directory of a single-sided diskette can
hold 64 entries, while the root directory of a
double-sided diskette can hold 112 entries. The root
directory of a high-capacity diskette can hold 224
entries. There can be 512 entries in the root directory
of a fixed disk.

5-5

Unlike the root directory, subdirectories can contain
any number of entries, limited only by the amount of
available space on the disk.

Subdirectory names follow the same format as
filenames. They can consist of 1 to 8 characters
followed by an optional extension of a period and 1 to 3
characters. All characters valid for filenames are also
valid for subdirectory names.

Accessing Your Subdirectories

You need to know how to get to your subdirectories
and how to access files located in a subdirectory other
than the one you are working in. This section
discusses:

The current directory

The CHDIR command (Change Directory
command)

Specifying a path to a file

Using the PATH command

Using PATH in a batch file

The Current Directory

The current directory is the one you are currently
working in or the one you were working in on a
different drive. DOS remembers which directory was
current on each of your drives, even though you may
not be presently accessing any of those drives. When
DOS starts, the root directory is the current directory
(until you change directory using the CHDIR
command).

5-6

Changing Directories with CHDIR

Use the CHDIR (CD) command to move in and out of
your directories (make a different directory the current
directory). For example, if you are in the root
directory, and want to work with files in
\SALES\LINDA\REPORTS, type:

Ocd \SALES\LINDA\REPORTS (Press Enter)

You must "go through" SALES and LINDA to get to
REPORTS. The leading backslash is really not
necessary if you are currently in the root directory.

If you are in LINDA and you want to change to the
REPORTS subdirectory, you type:

Ocd reports (Press Enter)

You always get back to the root directory no matter
where you are in the directory structure, by typing:

Ocd \ (Press Enter)

The backslash ( \ ) signifies the root directory.

The longest path that you can specify with CHDIR is
64 characters.

Specifying a Path to a File

When you want DOS to locate a file, and you do not
specify a particular directory, DOS searches only the
current directory of your default drive.

DOS can search for a file in a directory other than the
current directory of your default drive. To do so, DOS
must know three things — the drive, the name of the
directory, and the name of the file.

These three components can be combined to create a
path to a file. For example, if your default drive is A,

5-7

and you want to copy a file named WEEKLY. REP

from drive C in the directory

\ SALES \ RUTH \ REPORTS to drive A, type:

A>copy c:\sales\ruth\reports\weekly.rep (Press Enter)

This command copies the file WEEKLY.REP from a
directory three levels below the root on drive C to the
current directory on drive A. Note that the filename is
the last item in the path.

Using the PATH Command

You can use the PATH command to tell DOS where to
search for executable files that it does not find in the
current directory. This search is valid only for files
with an extension of .EXE .BAT, or .COM. Data files
cannot be located using PATH.

To start a search from the root directory, the path
specified in the PATH command must begin with a
backslash. Otherwise, the search begins at the current
directory.

Let's suppose that you have several applications that
require BASIC.COM in order to run. BASIC.COM is
only on drive C in the directory
\ ACCTNG\LEE\PROGRAMS. Your application
programs are on diskette and may be run from either
drive A or drive B.

You can set the PATH so that DOS looks for
BASIC.COM, or any other executable file that may be
needed to run your applications or manage your files.
DOS searches the directories in the exact order that you
specify in the PATH command. Given the diagram at
the beginning of the chapter, a valid path is:

Opath c:\sales\l inda\reports\;c:\acctng\lee\programs

After you start the application program, at a specific
point, BASIC.COM is required in order for the
program to continue. In this example, DOS searches

5-8

the current directory of the default drive and then the
path that you set when you started the computer. DOS
finds the required file in

\ ACCTNG\LEE\PROGRAMS on drive C. Your
application program can continue because
BASIC.COM has been invoked.

For more information, see the PATH command in
Chapter 7 of this book.

Using PATH in a Batch File

You can avoid having to set the PATH each time you
turn on your computer. Include the names of your
most-used directories in a PATH statement in an
AUTOEXEC.BAT file in the root directory of the disk
from which you start DOS.

AUTOEXEC.BAT is a special type of batch file that
DOS looks for when you first start your computer. If
DOS finds AUTOEXEC.BAT in the root directory, it
executes the statements it finds there. The previous
example is a valid path that can be included in an
AUTOEXEC.BAT file.

5-9

Using Directory Commands

The following commands help you create and manage
your subdirectories and directory structure:

• MKDIR (MD) — used in making a new
subdirectory.

• RMDIR (RD) — used in removing a subdirectory.

• CHDIR (CD) — used in displaying and changing
the current directory.

• TREE — used in displaying the entire directory
structure of a disk.

5-10

Making a Subdirectory

Use the MKDIR (MD) command to make a new
subdirectory. Be sure to include the appropriate drive
and path, ending with the name of the new subdirectory
you want created.

Let's assume you want to add the PAYMENTS

subdirectory one level below

SALES \ LINDA \ REPORTS. Make sure you are in

the root directory of the correct disk drive and type the

following:

OMD \SALES\LINDA\REPORTS\PAYMENTS (Press Enter)

The resulting subdirectory structure looks like this:

ROOT DIR

SALES

ACCTNG

LINDA

RUTH

LEE

RAE

REPORTS

PROGRAMS

REPORTS

PAYMENTS

Weekly. rep Baslc.com

5-11

Assume you want to add a subdirectory for a third
salesperson just below the SALES subdirectory. The
salesperson is Eileen. If you are in the root directory,
type:

Omd \sales\eileen (Press Enter)

If you are in the SALES directory, type:

Omd eileen (Press Enter)

The directory structure of your fixed disk now looks
like this:

R00TDIR

SALES

ACCTNG

LINDA

RUTH

EILEEN

LEE

RAE

REPORTS

PROGRAMS

REPORTS

PAYMENTS

Weekly. rep Basic.com

5-12

Removing a Subdirectory

Use the RMDIR (RD) command to remove a
subdirectory. You cannot remove a subdirectory by
using the ERASE or DEL commands. Before removing
a subdirectory, keep the following in mind:

• A subdirectory can be removed only if it is empty.
That is, it contains only the special entries (.) and
(..). When you display the contents of a
subdirectory, using the DIR command, you see
those two special entries listed.

• Only one subdirectory can be removed at a time —
only the last one specified in the path.

• The root directory and the current directory cannot
be removed.

Let's assume you want to remove the REPORTS
subdirectory from \ SALES \ RUTH \ REPORTS.

• If you are in the root directory, change directory to
the subdirectory you want to remove by typing CD
\ SALES \ RUTH \ REPORTS.

• Type erase *.* to remove all files in the

\ SALES \ RUTH \ REPORTS subdirectory.

Note: No files are erased from the SALES or
RUTH subdirectories, only from the
REPORTS subdirectory.

• Change directory to the level above the REPORTS
subdirectory that you want to remove by typing cd
\ SALES \ RUTH.

• Type RD REPORTS to remove the subdirectory.

5-13

The directory structure now looks like this:

ROOTDIR

SALES

ACCTNG

LINDA

RUTH

EILEEN

LEE

REPORTS

RAE

PROGRAMS REPORTS

PAYMENTS

Basic.com

Displaying and Changing the Current Directory

As previously mentioned, you change from one
subdirectory to another using the CHDIR (CD)
command. See the section entitled, "Changing
Directories with CHDIR" earlier in this chapter for
more information.

You can also display which subdirectory you are
currently working in by typing:

(Press Enter)

5-14

Displaying the Directory Structure

Use the TREE command to find out the names of each
subdirectory on a disk. For example, to see the
directory structure for disk C, type the following:

A> TREE C:

For more information on the TREE command, see
Chapter 7 of this book.

Where DOS Looks for Commands and
Batch Files

When you type a command, if it is an external file, DOS
must locate the command file in order to execute the
command. You must specify the location (path) that
describes which drive and directory the command file is
in. You do this by typing the path before the command
itself. You can use the PATH command to tell DOS
what paths to search if it does not find the command
file in the current directory or the path specified on the
command line.

Note: This search is only valid for files with a
.EXE, .BAT, or .COM filename extension. Data
files cannot be located by using the PATH
command.

5-15

Notes:

5-16

Chapter 6. Standard Input and Standard
Output

Contents

Introduction 6-3

Redirection of Standard Input and Output Devices . 6-3

Piping of Standard Input and Output 6-6

DOS Filters 6-7

6-1

Notes:

6-2

Introduction

This chapter describes how you can use redirection,
piping, and filters with standard input and standard
output. It also describes how to invoke a secondary
command processor.

Use redirection of standard input and standard output
to change the standard input device or standard output
device.

Use piping of standard input and standard output to use
the output of one program as the input to another
program.

Use filters to sort the input or output of a program, or
to find the occurrence of a string in a text file, or to
display a screen of data and then pause with the
message — More — .

Redirection of Standard Input and
Output Devices

DOS provides internal functions that programs can use
to receive input and display or print output. These
functions are called standard input and standard output.

The DOS standard input and output redirection feature
allows a program to receive its input from a source
other than the standard input device, or direct its output
to a device other than the standard output device.

When you first start DOS, the standard input device is
the IBM Personal Computer keyboard, and the
standard output device is the display unit (screen).
However, DOS lets you specify input and output
devices other than the keyboard and the screen. Refer

6-3

to the CTTY command, described in Chapter 7 of this
book to see how you can specify a remote terminal as
the standard input and output device instead of the
keyboard and screen.

DOS handles the mapping of the logical (standard input
and output) devices to the real devices in a way that is
not apparent to the application program. The
application program does not need to be aware of the
physical device that is actually being used for standard
input and standard output.

Note: Any output sent to the standard error device
cannot be redirected.

This means that you can run your application program
using the keyboard and screen for your input and
output device, and then run your application at another
time using a remote terminal for your input and output
device. You do not have to change the application
program, which continues to use the standard input and
standard output. DOS goes to the correct physical
device on behalf of the application program.

The standard input and output devices can be
redirected to or from files or other devices by the
following DOS command line parameters:

> [d: ] [path]filename[.ext]

Causes filename[.ext\ to be created (or truncated
to zero length) and then assigns standard output to
that file. All output that would normally have gone
to the screen from the command is placed in the
file.

> > [d:][path]filename[.ext]

Causes filename[.ext] to be opened (created if
necessary) and positions the write pointer at the
end of the file so that all output is appended to the
file.

6-4

< \.d'- ] \path]filename[.ext\

Causes standard input to be assigned to
filename[.ext\. All input to the program comes
from this file instead of from the keyboard.

CAUTION

When using this method of providing input to
a program, be sure all of the program's input
is in the file. If the program attempts to obtain
more input after end-of-file is reached, DOS
is unable to supply the input, and processing
stops. You may have to restart the system by
pressing Ctrl-Alt-Del.

Note: If an application does not use DOS
function calls to perform standard input and output
(for example, it puts text directly into the video
buffer), then redirection will not work for that
application.

Example: In the following example, the output of the
DIR command is sent to the printer:

A>dir >prn

In the following example, the output of the DIR
command is sent to the file DIRLIST:

A>dir >dirlist

In the following example, the program MYPROG will
receive its input from file INPUT.TXT, instead of
from the keyboard:

A>myprog <input. txt

6-5

Piping of Standard Input and Output

The DOS piping feature allows the standard output of
one program to be used as the standard input to
another program. DOS uses temporary files to hold the
input and output data being piped. These temporary
files are created in the root directory of the default
drive.

The programs being piped must not cause the piping
files to be erased or modified.

Piping is the chaining of programs with automatic
redirection of standard input and output (refer to
"Redirection of Standard Input and Output Devices"
in this chapter for additional information). The names
of the programs to be chained are separated by the
vertical bar ( | ) character on the command line.

The following are typical examples of using the piping
feature for a program that does all of its input and
output to the standard input and output devices. For
example, if the program named SORT ABC read all of
its input from standard input, sorted it, and then wrote
it to the standard output device, the command:

A>dir | sortabc

would generate a sorted directory listing. This causes
all standard output generated by the DIR command to
be sent to the standard input of the SORT program.

To put the sorted directory in a file, you would type:
A>dir | sort > file

If you want the file to contain only the directory
entries for subdirectories, you could type:

A>dir ! find"<DIR>" ! sort > file

6-6

DOS Filters

A filter is a program or command that reads data from
a standard input device, modifies the data, then writes
the result to a standard output device. Thus, the data
has been "filtered" by the program. For example, one
of the filters on your DOS diskette is called SORT.
SORT reads input from the standard input device
(normally the keyboard), sorts the lines of data, then
writes the sorted results to the standard output device
(normally the screen). With the redirection capabilities
described earlier in this chapter, you can cause SORT
to receive its input from some other source, and to
send its output to a different destination. For
example,

A>sort <myfile >result

will cause SORT to read the file MYFILE, sort the
lines within it, and write the sorted output to file
RESULT.

By using the piping feature, you can cause a filter to
receive its input from the output of another command,
or to send its output to the input of another command.
For example,

A>dir | sort

causes the output listing from the DIR command to
be used by SORT as its input. The listing will be
sorted and the result displayed on the standard output
device.

6-7

There are three filters on your DOS diskette, and they
are described as individual commands in Chapter 7.
They are:

SORT Sorts text data.

FIND Searches files for occurrences of specified
strings of text.

MORE Displays a screen full of data at a time, then
pauses with the message —More — .

You can add your own filter to the filters that have
been supplied; just write a program that reads its input
from the standard input device, and writes its output
to the standard output device.

Note: If an application does not use DOS
function calls to perform standard input or output
(for example, it puts text directly into the video
buffer), filters will not work for that application.

6-8

Chapter 7. DOS Commands

Contents

Introduction 7-5

DOS Commands and the Network 7-7

Types of DOS Commands 7-8

Entering a DOS Command 7-9

Information Common to All DOS Commands ... 7-10

DOS Commands 7-13

ASSIGN (Drive) Command 7-14

ATTRIB (Attribute) Command 7-17

BACKUP Command 7-19

Batch File Commands 7-24

Creating a Batch File 7-26

Executing a Batch file 7-27

The AUTOEXEC.BAT File 7-27

Creating an AUTOEXEC.BAT file 7-28

Creating a Batch File with Replaceable

Parameters 7-28

Executing a Batch File with Replaceable

Parameters 7-29

ECHO Subcommand 7-30

FOR Subcommand 7-32

GOTO Subcommand 7-33

IF Subcommand 7-34

PAUSE Subcommand 7-38

REM (Remark) Subcommand 7-39

SHIFT Subcommand 7-40

7-1

BREAK (Control Break) Command 7-43

CHDIR (Change Directory) Command 7-45

CHKDSK (Check Disk) Command 7-48

CLS (Clear Screen) Command 7-52

COMMAND (Secondary Command Processor)
Command 7-53

COMP (Compare Files) Command 7-55

COPY Command 7-60

CTTY (Change Console) Command 7-72

DATE Command 7-74

DEL (Delete) Command 7-77

DIR (Directory) Command 7-79

DISKCOMP (Compare Diskettes Only)

Command 7-84

DISKCOMP Compatibility 7-88

DISKCOPY (Copy Diskettes Only) Command .. 7-90

DISKCOPY Compatibility 7-94

ERASE Command 7-96

EXE2BIN Command 7-98

FDISK Command 7-101

FIND Filter Command 7-102

FORMAT Command 7-105

FORMAT Compatibility 7-110

GRAFT ABL (Load Graphics Table) Command 7-113

7-2

GRAPHICS (Screen Print) Command 7-115

JOIN Command 7-118

Why Use JOIN? 7-122

KEYBxx (Load Keyboard) Command 7-123

Allowable Dead Key Combinations ... 7-126

LABEL (Volume Label) Command 7-127

MKDIR (Make Directory) Command 7-130

MODE Command 7-132

MORE Filter Command 7-139

PATH (Set Search Directory) Command 7-140

PRINT Command 7-143

PROMPT (Set System Prompt) Command ... 7-149

RECOVER Command 7-153

RENAME (or REN) Command 7-156

RESTORE Command 7-157

RMDIR (Remove Directory) Command 7-161

SELECT Command 7-162

SET (Set Environment) Command 7-164

SHARE Command 7-167

SORT Filter Command 7-169

SUBST(Substitute) Command 7-172

Why Use SUBST? 7-177

SYS (System) Command 7-178

7-3

TIME Command 7-180

TREE Command 7-182

TYPE Command 7-185

VER (Version) Command 7-186

VERIFY Command 7-187

VOL (Volume) Command 7-188

7-4

Introduction

You can use DOS commands to:

Compare, copy, display, erase, rename files.

Format fixed disks and diskettes.

Execute system programs, such as EDLIN,
DEBUG, and LINK, plus your own programs.

Set various printer and screen options.

Request DOS to pause.

Transfer DOS to another diskette.

Cause printer output to be directed to the
Asynchronous Communications Adapter.

Recover a specific file from a damaged disk, or
recover the entire disk or diskette.

Print the contents of a graphics display screen on
a printer.

Print files on the printer while the system is doing
other work.

Backup and restore files on a fixed disk.

Define a remote device as your primary console.

Sort text data.

Search files for occurrences of specified strings of
text.

Display a screen full of data at a time.

Set new system prompt.

7-5

Set the system environment.

Convert .EXE files to .COM files.

Install file sharing.

Make a file read-only.

Add or change a disk volume label.

Ask DOS to check for Ctrl-Break to exit a
program or command at any time.

Create, remove, and change subdirectories.

Display all the directories on a disk.

Check for disk errors.

Set the date and time.

Find out what's on a disk.

Select the date and time format.

Join a drive to a directory on another drive so that
you can access a drive through a subdirectory.

Substitute a drive letter for another drive or
directory in order to access that drive or directory
using only the drive letter.

7-6

DOS Commands and the Network

You can use most of the DOS commands on network
disks, directories, and printers.

For example, use the DIR command to list the
contents of a network disk or directory.

Use the COPY command to copy files from a network
disk or directory. You can copy the files to your own
disk or to a network disk or directory.

There are a few DOS commands that you cannot use
with network disks, directories, or printers that you
are using (or disks and directories that you are
sharing) on the network. Don't use:

. CHKDSK

• DISKCOMP

Note: Instead of DISKCOMP, use COMP

(Compare) to compare files.

. DISKCOPY

Note: Instead of DISKCOPY, use the
COPY command to copy files.

FORMAT

JOIN (cannot JOIN a network drive to a local
drive)

RECOVER

SUBST (cannot SUBST a drive letter for a
network path)

SYS

7-7

• PRINT (cannot use PRINT on a network server
computer)

. FDISK

• LABEL (cannot change the label on a network
disk)

Note: Using these commands with a network
device causes an error message.

Of course, these commands are valid for your real
disks, directories, and printers.

Types of DOS Commands

The two types of DOS commands are internal
commands and external commands.

Internal commands execute immediately because they
are built into DOS. Therefore, once DOS is loaded,
you do not need the DOS diskette in a drive to use
these commands.

External commands are on disks as program files.
They must be read from the disk before they are
executed. This means that the disk containing the
command must be in a drive, or DOS is unable to find
the command.

Any file with a filename extension of .BAT, .COM or
.EXE is considered an external command. This allows
you to develop your own unique commands and add
them to the system. (For example, programs such as
FORMAT.COM and COMP.COM are external
commands.)

When you select an external command, you do not
have to include the filename extension.

7-8

Entering a DOS Command

Use the following format notation to enter DOS
commands:

[ ] Items shown inside square brackets are

optional. To include optional items, type
only the information inside the brackets.
Do not type the brackets.

CAPS Words shown in capital letters are called
keywords. The DOS command names are
keywords. You can type keywords in any
combination of uppercase and lowercase
letters.

italics Items shown in lowercase italic letters mean
that you are to substitute the item. If italic
items are inside brackets, then they are
optional. For example,

filename

indicates that you should type the name of
your file in place of the word filename.

| A vertical bar means either/or. Choose one

of the separated items and type it as part of
the command. For example,

ON I OFF

indicates that you should type either ON or
OFF, but not both. Do not type the vertical
bar.

An ellipsis indicates that you can repeat an
item.

7-9

Include all punctuation such as commas, equal signs,
question marks, asterisks, colons, slashes and
backslashes. Punctuation shown inside brackets is
optional.

Information Common to All DOS
Commands

The following information applies to all DOS
commands:

• The DOS prompt consists of the default drive
letter and the character ">." For example, A> is
the DOS prompt that denotes A as the default
drive. You can change the DOS prompt by using
the PROMPT command.

• When a command has finished executing, the
DOS prompt reappears on the screen. If no error
messages appear before the DOS prompt returns,
the command has been executed successfully.

• Commands are usually followed by one or more
parameters.

• You can type commands in uppercase or
lowercase or a combination of both. For
example, you can type:

Dir A:

• DOS searches the current directory of the drive
you specify or the default drive (if you do not
specify a drive) to find a command or batch file
you typed. If not found, and you have specified a
PATH command, DOS searches the directories
listed in the path.

7-10

Commands that allow you to enter filenames can
accept a path (directory) name before the
filename.

Commands and parameters must be separated by
delimiters (space, comma, semicolon, equal sign,
or the tab key). The delimiters can be different
within one command. For example, you could
type:

A>copy oldfile.rel ;newfile.rel
A>rename, this file thatfile

Do not separate the three parts of a filespec
(d:filename.ext). The colon and period already
serve as separators.

In this book, a space is used as the delimiter in the
commands for readability.

Also in this book, when we say "Press any key"
we mean "Press any character key."

To stop a command while it is executing, press
Ctrl-Break. Ctrl-Break is recognized only while
the system is reading from the keyboard or
printing characters on the screen, unless you have
used BREAK=ON in your configuration file or
have issued a BREAK ON command. Thus, the
command may not end immediately when you
press Ctrl-Break.

Commands start executing only after you press
the Enter key.

Global filename characters and device names are
not allowed in a command name. You can only
use them in filenames and filename extensions.

For commands displaying a large amount of
output, you can use the Pause Screen function to
suspend the display of the output. Press any
character key to continue the display.

7-11

You can use the function keys and the DOS
editing keys described in Chapter 2 of the DOS
User's Guide while typing DOS commands.

Drives are referred to as source drives and target
drives. A source drive is the drive you transfer
information from. A target drive is the drive you
transfer information to.

When an external command is typed, DOS
searches for it in the current directory of the
default or specified drive. If not found, DOS
continues searching for it in the directories listed
in the most recent PATH command.

If you type any of these characters <, >, or [ in a
command, DOS treats them as redirection and
piping characters. Refer to Chapter 6 "Standard
Input and Standard Output" for information on
redirection and piping.

For example, if you type the following ECHO
command, the > character is treated as a
redirection character, not the greater-than
character.

A>echo filel > f i 1 e2

Therefore, the string FILE1 is placed in the file
FILE2.

7-12

You can specify a drive and path before external
commands. This means that the external
command file can be in a directory other than the
current directory. For example, if the file
FORMAT.COM is in the directory \LEVEL1
on drive B, you can type:

A>b: \level 1\ format

DOS Commands

This section presents a detailed description of the
DOS commands. The commands appear in alphabetic
order. The description includes the purpose, format,
and type of each command. Examples are provided
where appropriate.

7-13

ASSIGN (Drive)
Command

Purpose: Instructs DOS to route disk I/O requests for one
drive into disk I/O requests for another drive.

Format: [d: ][path] ASSIGN [x[=]y [...]]

Type: Internal External

Remarks: Specify the parameters:

[d:][path] before ASSIGN to specify the drive and
path that contains the ASSIGN command file.

x to specify the drive to which current disk I/O
requests are sent.

y to specify the drive letter that you want disk I/O
requests to now be sent.

The first drive letter x is internally converted by
DOS to the second drive letter y. Both x and y must
physically exist (a diskette, fixed disk or block device
driver such as VDISK). Do not type the colon after
the drive letters x and y.

Type ASSIGN with no parameters to reset all drive
assignments so that normal drive assignments
resume.

Note: This command has been included to assist
you with applications that were designed to
perform their disk operations specifically on
drives A and B (those applications that do not
allow you to specify a drive). By using a
command such as,

7-14

ASSIGN (Drive)
Command

A>assign a=c b=c

those applications can be made to use drives
other than A and B, such as a fixed disk.

Reassignment of drives should only be used
when necessary for these cases. It should never
be used with the BACKUP, RESTORE,
LABEL, JOIN, SUBST, or PRINT commands.

Also, do not reassign drives when running DOS
in normal operations. Doing so can hide the true
device type from commands and programs that
require actual drive information. Note that
FORMAT, DISKCOPY and DISKCOMP
ignore any drive reassignments.

If you will be developing an application
program, we recommend that you avoid using
specific drive assignments within your program,
but instead, allow the user to specify the
drive(s) to be used.

Example: The following example assigns all requests for drive
A to drive C. Thus, if you issue DIR A:, DOS
displays the directory that is on physical drive C:

A>assign a=c

7-15

ASSIGN (Drive)
Command

The following example assigns any requests for
drive A or drive B to drive C.

A>assign a=c b=c

The following example resets any previous drive
assignments so that requests for drive A go to drive
A, etc.

A>assign

7-16

ATTRIB (Attribute)
Command

Purpose: Allows you to set or reset the Read-Only file

attribute, or to display the current setting of that
attribute.

Format: [d:][path]ATTRlB [+R | -R] [d:][path]filename[.ext]

Type: Internal External

* * *

Remarks: Specify the parameters:

[d:][path] before ATTRIB to specify the drive and
path that contains the ATTRIB command file.

+R to set the read attribute of the specified file to
read-only.

-R to remove the read-only attribute of the specified
file.

[d:][path\filename[.ext] to specify the file you want to
mark as read-only. Global filename characters are
allowed.

Example: The following example sets the attribute of the file
name FILE1.TXT to read-only.

A>attrib +r filel . txt

The following example displays the current setting
of the Read-Only attribute for the file FILE1.TXT.

A>attrib filel.txt

7-17

ATTRIB (Attribute)
Command

The result is:

R A:\FILE1.TXT

The following example removes the read-only
attribute from the previous example.

A>attrib -r filel .txt

The following example displays the current setting
of the Read-Only attribute for the file FILE1.TXT.

A>attrib filel.txt

The result is:

A:\FILE1.TXT

The following example sets the attribute of the file
C:\PROGl.BAS to read-only.

A>attrib +r c:\progl.bas

7-18

BACKUP

Command

Purpose: Backs up one or more files from one disk to another.
The drive specifiers of the disks must be different.

Format: [d: ][path] BACKUP d:[path][filename[.ext]] d:

[/S][/M][/A][/D:mm-^]

Type: Internal External

** *

Remarks: You can back up files from a:

• Fixed disk to a diskette

• Diskette to a diskette

• Diskette to a fixed disk

• Fixed disk to a fixed disk

Specify the parameters:

[d:]\j)ath] before BACKUP to specify the drive and
path that contains the BACKUP command file.

d: to specify the drive that contains the files you
want to BACKUP (source). [path]\filename[.ext]] to
specify the name of the file you want to BACKUP.

d: to specify the drive that will contain the backed up
files (target).

/S to back up subdirectory files in addition to the
files in the specified or current directory.

/M to back up files that have been modified since
the last backup.

7-19

BACKUP

Command

/A to add the files to be backed up to the files
already present on the backup disk.

/D to back up files that have been modified on or
after the specified date. The format of the date
specified will be [mm-dd-yy] or [dd-mm-yy] or
\yy-mm-dd\ depending on the country code you
selected using the SELECT or COUNTRY
commands.

Notes:

The disk that contains the file you want to back
up is called the source. The disk where the
backup file is placed is called the target. For
example, if you want to back up a file from your
fixed disk to a diskette, the fixed disk is the
source and the diskette is the target.

Global filename characters are allowed in the
filename and extension. Therefore, you can
backup all files (including subdirectory files)
from the source drive C to the target drive A by
typing:

A>backup c: \*.* a:/s

BACKUP is not the same as COPY. COPY
makes an exact duplicate of the file. BACKUP
files have control data included that the
RESTORE command uses. Therefore, you
cannot use backed up files as data files until
they are restored. Refer to the RESTORE
command in this chapter for information on
using RESTORE.

7-20

BACKUP

Command

4. If you are sharing files, you can only BACKUP
files that you have access to. If you attempt to
access a file that you do not have access to, the
following message appears:

PATHNAME\FILENAME.EXT

Not able to backup at this time

5. If the target is a new diskette, use DOS to
format the diskette before you backup files.

6. If the diskette contains files, BACKUP erases
the files already present on the diskette unless
you specify /A parameter.

7. If the source or target is removable, you are
prompted to insert the source or target diskette
into the drive.

8. After BACKUP fills up a diskette, you are
prompted to insert a new diskette. Label each
diskette and record the date and diskette
number.

9. BACKUP displays the name of each file as it is
backed up. Label each backup diskette in
consecutive order because, when the files are
restored, you are prompted to insert the backup
diskette in order.

10. The BACKUP command sets the exit code as
follows:

Normal completion

1 No files were found to backup

2 Some files not backed up due to file
sharing conflicts

7-21

BACKUP

Command

Example:

3 Terminated by user (Ctrl-Break)

4 Terminated due to error

These codes can be used with the batch
processing IF ERRORLEVEL subcommand.

11. If the target is a fixed disk, the backup files are
placed in a subdirectory named \ BACKUP. If
the target is a diskette, the backup files are
placed in the root directory.

12. If the source is a diskette, it should not be write
protected because BACKUP needs to mark the
files as being backed up (/M).

13. Do not use BACKUP with a drive letter that has
been assigned or substituted as this can hide the
true drive letter that BACKUP is using.

14. Do not use BACKUP while a JOIN is in effect
because the tree structure may be invalid when
you RESTORE.

The following example backs up all files from the
fixed disk drive C to the diskette in drive A.

A>backup c:

a:/s

Note: To back up a 10M byte fixed disk onto
double-sided 9 sector diskettes, you need
approximately 25 diskettes.

7-22

BACKUP

Command

The following example backs up the file named
FILE. TXT from drive A to drive C.

A>backup a:f lie. txt c:

The following example backs up all files from drive
A that have been modified since the date 8-21-84.

A>backup a: c :/d:8-21-84

The following example adds the files on drive A to
the backed up files already on the diskette in drive B.

A>backup a: b:/a

7-23

Batch File
Commands

Purpose: Batch commands are DOS commands that are

contained in a special file called a batch file. When
you execute a batch file, DOS executes the
commands you include in the batch file.

Format: [d:][path]filename[.BAT] [parameters]

Type: Internal External

Remarks: A batch file is a file containing one or more

commands that DOS executes one at a time. All
batch files must have a filename extension of .BAT.

You can pass parameters (using replaceable
parameters) to the filename.BAT file when the file is
executed. Therefore, the file can do similar work
with different data during each execution.

You can create a batch file by using the Line Editor
(EDLIN), or by using the COPY CON command
directly from the standard input device.

Notes:

Do not enter the name BATCH (unless the
name of the file you want to execute is
BATCH.BAT).

Do not name batch files with internal command
names.

3. You do not need to type the filename extension
.BAT to execute a batch file.

7-24

Batch File
Commands

4. The commands in the file named filename. BAT
are executed.

5. There are seven subcommands that can be used
to control batch processing: ECHO, FOR,
GOTO, IF, SHIFT, PAUSE, and REM. They
are explained in the following pages.

6. If you remove a diskette containing a batch file
being processed, DOS prompts you to insert it
again before the next command can be read.

7. The last command in a batch file may be the
name of another batch file. This allows you to
invoke one batch file from another when the
first is finished. If a batch file references
another batch file, the second batch file does
not return to the first batch when if finishes
unless the first batch file contains the
COMMAND command.

8. DOS remembers which directory the batch file
was started from. Therefore, the commands
within the batch file may change the current
directory during execution.

9. Batch files execute quickly if placed on a virtual
disk. Refer to Chapter 4 "Configuring Your
System" for information on virtual disks
(VDISK.SYS).

7-25

Batch File
Commands

Creating a Batch File

You can create a batch file by using an editor or by
using the COPY command directly from the standard
input device. Follow these steps to create a batch
file using the COPY command.

1 . At the DOS prompt type:

A>copy con filename .bal

Substitute the name you want for your batch file
for filename.

2. Press Enter.

3. Type the commands you want to include in the
batch file. Press Enter after you type each
command.

Note: If you make a mistake typing a
command, press Ctrl-Break. Pressing
Ctrl-break ends the COPY command
without saving the batch file. Then repeat
the procedure again.

4. Press F6 and then Enter when you have finished
typing commands. This ends the COPY
command and saves the batch file. This
message is displayed:

1 File(s) copied
A>

7-26

Batch File
Commands

Executing a Batch file

Batch files are executed by typing the name of the
batch file at the DOS prompt and then pressing
Enter. For example, to execute a batch file named
EXAMPLE.BAT, at the DOS prompt type:

A>example

then press Enter.

You do not need to type the batch filename
extension .BAT.

To stop the execution of a batch file, press
Ctrl-Break. The command being executed ends and
the following prompt is displayed:

Terminate batch job (Y/N)?

Type y to terminate the batch file. The remaining
commands are ignored and the DOS prompt is
displayed.

Type n to continue executing the remaining
commands.

The AUTOEXEC.BAT File

Every time you start DOS, the command processor
searches for a file named AUTOEXEC.BAT in the
root directory on the disk that DOS was started
from. An AUTOEXEC.BAT file is a special type of
batch file that is automatically executed when you
start or restart DOS. An AUTOEXEC.BAT file is
useful if you want to execute certain commands

7-27

Batch File
Commands

every time you start DOS. For example, you can
create an AUTOEXEC.BAT file that sets the DOS
path by including the PATH command in the file.

Creating an AUTOEXEC.BAT file

An AUTOEXEC.BAT file must be created in the
root directory of the disk you start DOS from. You
are not prompted for the date and time when you
start DOS, unless you include the DATE and TIME
commands in the AUTOEXEC.BAT file.

Creating a Batch File with Replaceable
Parameters

Within a batch file you can include dummy
parameters that can be replaced by values supplied
when the batch file executes.

For example, if the batch file EXAMPLE.BAT
contains these commands:

copy %l .mac %2.mac
type %2.prn
type %0.bat

the replaceable parameters %0, %1, and %2 are
replaced sequentially by the parameters you supply
when you execute the file. The replaceable
parameter %0 is always replaced by the drive
specifier, if specified, and the filename of the batch
file. In the AUTOEXEC.BAT file, %0 is not set to
any value.

7-28

Batch File
Commands

Notes:

1 . Up to 10 dummy parameters (%0 - %9) can be
specified within a batch file, more than 10
parameters can be specified on a command line
(see SHIFT subcommand).

2. If you want to use % as part of a filename
within a batch file, you must specify it twice.
For example, to specify the file ABC %. EXE
you must type it as ABC%%.EXE in the batch
file.

Executing a Batch File with Replaceable
Parameters

To execute the EXAMPLE.BAT file and pass
parameters, type the batch filename followed by the
parameters you want sequentially substituted for

%1, %2, etc.

For example, you can type:

A>example arprogl b:prog2

EXAMPLE is substituted for %0, A:PROGl for
%1, and B:PROG2 for %2.

The result is the same as if you typed each of the
three commands (in the EXAMPLE.BAT file) from
the console with their parameters, as follows:

A>copy a: progl .mac b:prog2.mac
A>type b:prog2.prn
A>type example.bat

7-29

Batch File
Commands

ECHO Subcommand

Purpose: Allows or inhibits the screen display of DOS

commands executed from a batch file. It does not
interfere with messages produced while the
commands are executing.

Format: ECHO [ON | OFF | message]

Type: Internal External

* * *

Remarks: Batch commands are normally displayed on the

screen as they are read from the batch file. ECHO is
ON after power-on or system reset. ECHO ON
displays all the commands on the standard output
device as they are executed. ECHO OFF stops the
display of commands on the screen (including the
REM command).

ECHO message displays message on the standard
output device regardless of the current ON or OFF
state. In this way, you can cause specific messages to
be displayed even when ECHO has been turned off.
If ECHO is issued with no parameters, the current
ECHO state (ON or OFF) is displayed.

Example: In this example, the batch file contains the following:

echo off
rem ****
dir a:/w
echo on
dir a:/w

command display is off

7-30

Batch File
Commands

When this batch file is executed, the following
display occurs:

A>echo off

Volume on drive A has no ID

Directory of A: \

filel.ext file2.ext

2 file(s) xxxxx bytes free

A>echo on

A>dir a : /w

Volume on drive A has no ID

Directory of A: \

filel.ext file2.ext

2 file(s) xxxxx bytes free

In the above example, the ECHO OFF is displayed.
The rem command and dir a:/w are not displayed
because ECHO is OFF, but the output of the dir is
still displayed. Then, echo on is executed, and the
command dir a:/w is displayed.

7-31

Batch File
Commands

FOR Subcommand

Purpose: Allows iterative execution of DOS commands.
Format: FOR %%variable IN (set) DO command

Type: Internal External

***

Remarks: The % % variable is sequentially set to each member
of set and then the command is evaluated and
executed. If a member of set is an expression
involving * and/or ?, then the % % variable is set to
each matching filename from disk. Path names are
allowed in set.

Note: % % is required if the FOR command is
included in a batch file. To type the FOR
command at the DOS prompt, only include one
%. For example you can type:

A>for %h in (filel) do dir

Example: In the following example, if you type the command:

for %%f in (progl.asm prog2.asm prog3.asm) do dir %%f

The result is the same as if you typed the following
three commamds:

dir progl.asm
dir prog2.asm
dir prog3.asm

Note: FOR subcommands cannot be nested;
that is, only one FOR subcommand can be
specified on a command line.

7-32

Batch File
Commands

GOTO Subcommand

Purpose: Transfers control to the line following the one

containing the appropriate label. A label is inserted
in a batch file as a colon (:) followed by the label
name.

Format: GOTO .-label

Type:

Internal External

Remarks: The GOTO label causes commands to be executed
beginning with the line immediately after -.label. If
-.label is not defined, the current batch file terminates
with the message Label not found. A label in a batch
file is defined as a character string where the first 8
characters are significant (make it different).

Example: In this example, the following batch file produces an
indefinite sequence of rem looping... and goto loop

messages on the screen:

.ioop

rem looping...

goto loop

Note that labels within a batch file are never
displayed while the batch file is executing. In the
example above, the line :LOOP would not be
displayed. Thus, unreferenced labels provide a handy
means for placing comments within your batch file
that are not displayed when the file is executed.

7-33

Batch File
Commands

IF Subcommand

Purpose: Allows conditional execution of DOS commands.
Format: IF [NOT] condition command

Type: Internal External

***

Remarks: The condition parameter is one of the following:

ERRORLEVEL number

string 1 = =string2

EXIST [d:][path]filename[.ext]

When the condition is true, then the DOS command
is executed. Otherwise, the DOS command is
skipped, and the next command in the file is
executed.

ERRORLEVEL number is true if the previous
program had an exit code of number or higher. The
number is specified as a decimal value.

string l = =string2 is true when string 1 and string 2 are
identical.

Note: The corresponding characters of string 1
and string2 must both be uppercase or lowercase
to be identical.

EXIST is true if filename is found in the specified
directory. Global filename characters (? and *) are
allowed in filename.

The NOT condition is true if the condition is false.

7-34

Batch File
Commands

Example: This example is for:

IF EXIST [d:][path]filename[.ext]

if exist filel goto abc

:abc
command

Execution of this command in a batch file is true
provided FILE1 is found in the current directory on
the default drive. The GOTO ABC is executed
causing the system to skip to the command following
the label : ABC. If FILE1 is not found, the GOTO
ABC would not be executed. Processing would then
continue with the next command in the batch file.

The following example is for:

IF string 1 = = string!

if %1 == John echo John was here!

Execution of a batch file containing this command
with JOHN given as the % 1 parameter would make
the condition true. The ECHO batch command
would then be executed displaying John was here! If
JOHN was not given as the %1 parameter, the
condition would have been false. The ECHO batch
command would not have been executed. Processing
would continue with the next command in the batch
file.

7-35

Batch File
Commands

The following example is for:

IF ERRORLEVEL number

myprogl

if errorlevel 1 echo myprogl failed

The above two commands are in a batch file;
MYPROG1 is a program that sets the errorlevel
when it completes its processing. In the simple case,
MYPROG1 sets the errorlevel to if it completed
processing successfully and sets errorlevel to 1 if
processing completed unsuccessfully. The batch file
conditional if errorlevel 1 echo ... tests for the
situation when MYPROG1 failed. If MYPROG1
completed processing unsuccessfully, the condition is
true and the ECHO batch command is executed.
The ECHO batch command displays the data (or
message) immediately following echo. If MYPROG1
was successful, the condition would not be true and
the ECHO batch command would not be executed.
Processing would then continue with the next
command in the batch file.

The following example is for:

IF NOT EXIST [d:][path]filename[.ext]

if not exist a:%l copy b:°/l a:
program

7-36

Batch File
Commands

The batch file that contains this command is going
to execute a program that requires a particular file to
be on drive A. The IF command is executed prior to
the program to make sure that the required file is on
drive A. If the file does not exist on drive A, the
condition is true. The COPY command is then
executed, copying the file from drive B to drive A to
satisfy the requirements of the program. If the file
does exist on drive A, the copy is not executed.
Processing then continues to execute the program.

Note: Only BACKUP and RESTORE

commands set an ERRORLEVEL that can be
tested. The facility is included to allow your own
programs to set an error code that can then be
tested by the IF ERRORLEVEL subcommand.

7-37

Batch File
Commands

PAUSE Subcommand

Purpose: Suspends system processing and displays the message
Strike a key when ready....

Format: PAUSE [remark]

Type: Internal External

***

Remarks: You can insert PAUSE commands within a batch file
to display messages and to give you the opportunity
to change diskettes between commands. To resume
execution of the batch file, press any key except
Ctrl-Break. (Ctrl-Break ends processing).

If you include the optional remark, the remark is also
displayed. The optional remark can be any string of
characters up to 121 characters long.

You can control how much of a batch file you want
to execute by placing PAUSE commands at strategic
points in the file. At each PAUSE command, the
system stops and gives you time to decide whether to
end processing. To end processing, press Ctrl-Break
and then type y. To continue processing, press n.

Example: If you type this PAUSE command in a batch file, the
following message is displayed:

A>pause Change diskette in drive A
Strike a key when ready. . ._

This PAUSE enables you to change diskettes
between commands.

7-38

Batch File
Commands

REM (Remark) Subcommand

Purpose: Displays remarks from within a batch file.
Format: REM [remark]
Type: Internal External

***

Remarks: The remarks are displayed when the batch execution
reaches the REM command. If ECHO is OFF, then
the remarks are not displayed.

Remarks can be any string of characters up to 123
bytes long.

You can use REM commands without remarks for
spacing within your batch file, for readability.

Example: If the following REM command is issued in a batch
file, this remark is displayed:

A>rem This is the daily checkout program

7-39

Batch File
Commands

SHIFT Subcommand

Purpose: Allows command lines to make use of more than 10
(%0 through %9) replaceable parameters.

Format:
Type:

SHIFT

Internal External

***

Remarks: Replaceable parameters are numbered %0 through
%9. If you wish to use more than 10 replaceable
parameters on a command line, you can use SHIFT
to get at parameters past the tenth. All parameters
on the command line are shifted one position to the
left, with the %0 parameter being replaced by the
%1 parameter, etc.. Each subsequent shift
command causes all the parameters to be shifted to
the left by one position. For example:

%0 =

= A

%1 =

= B

%2 =

= C

%3 =

= D

The SHIFT results are

%0 =

= B

%1 =

= C

%2 =

= D

7-40

Batch File
Commands

Example: This example demonstrates how the SHIFT

subcommand can be used in a batch file. If a batch
file named MYFILE.BAT contains the following
commands, and the default drive is A:

echo %0 %\ %2 %3

shift

echo %0 %1 %2 %3

shift

echo %0 %1 %2 %3

shift

echo %0 %1 %2 %3

shift

echo %0 %\ %2 %3

Invoke the batch file with the following parameters:

MYFILE PR0G1 PR0G2 PR0G3

7-41

Batch File
Commands

The result is:

A>echo MYFILE PR0G1 PR0G2 PR0G3
MYFILE PR0G1 PR0G2 PR0G3

A>shift

A>echo PR0G1 PR0G2 PR0G3
PR0G1 PR0G2 PR0G3

A>shift

A>echo PR0G2 PR0G3
PR0G2 PR0G3

A>shift

A>echo PR0G3
PR0G3
A>shift
A>echo

7-42

BREAK (Control Break)

Command

Purpose: Allows you to instruct DOS to check for a control

break whenever a program requests DOS to perform
any functions.

Format: BREAK [ON | OFF]

Type: Internal External

***

Remarks: Specify the parameters:

ON to set BREAK=ON. This means that DOS
checks for Ctrl-Break whenever it is requested. This
allows you to break-out of a program that produces
few or no standard device operations.

OFF to set BREAK=OFF. This means that DOS
only checks for Ctrl-Break during:

• Standard input operations

• Standard output operations

• Standard print device operations

• Standard auxiliary device operations
The default value is set at BREAK OFF.

7-43

BREAK (Control Break)
Command

If you type BREAK with no parameters, the current
state of the BREAK command (ON or OFF) is
displayed.

You can also turn on the extended checking by using
BREAK=ON in your configuration file. Refer to
"Configuring Your System" in Chapter 4.

7-44

CHDIR (Change Directory)

Command

Purpose: Changes the DOS current directory of the specified
or default drive, or displays the current directory
path of a drive.

Format: CHDIR [d:][path]

CD [d:][path]

Type: Internal External

***

Remarks: Specify the parameters:

Example:

[d:] to specify the drive specifier of the disk whose
current directory you want to change or display.

[path] to specify the current directory path. The path
cannot be more than 64 characters starting from the
root directory.

DOS looks in the current directory to find files
whose names are entered without specifying a path.
If you do not specify a drive, the default drive is
assumed.

Type CHDIR or CD with no parameters to display
the current directory path of the default drive.

The following example changes the current directory
of the default drive to its root directory:

A>chdir \

7-45

CHDIR (Change Directory)
Command

The following example displays the current
directory path of drive B.

A>cd b:

The following example changes the current
directory of drive B to the path
\LEVEL1\LEVEL2.

A>cd b:\levell\level2

The following example changes the directory of
drive B to the current directory path plus LEVEL3 :

A>cd b:level3

Thus, if the second example is used, the resultant
path would be:

\LEVEL1\LEVEL2\LEVEL3

The search for the LEVEL3 directory begins in the
directory that was current when the command was
issued, because no leading backslash ( \ ) was used.

The following example changes the current directory
of drive B to \ LEVEL 1.

A>cd b:\levell

The leading backslash ( \ ) tells DOS to start at the
root directory. DOS remembers the current
directory for each drive on the system, and any
reference to a drive will access the current directory.

7-46

CHDIR (Change Directory)

Command

Important: The true directory can be hidden by
ASSIGN, SUBST, and JOIN. The following example
describes a method of using C: while actually on A:.

A>join c: a:\cdrive
A> cd \cdrive
A>dir

7-47

CHKDSK (Check Disk)
Command

Purpose: Analyzes the directories, files, and the File

Allocation Table on the designated or default drive
and produces a disk and memory status report.

Format: [d:][path]CHKDSK

[d:]\path]\filename[.ext]][/F][/V]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before CHKDSK to specify the drive and
path that contains the CHKDSK command file.

[d:][path][filename[.ext]] to specify the filename. If
you specify a filename, CHKDSK displays the
number of noncontiguous areas occupied by the file
or files.

/F to have CHKDSK fix errors that are found in the
directory or file allocation table. The corrections are
written on the disk. If /F is not specified, CHKDSK
functions as though it were preparing to correct the
disk so that you can analyze the possible results of
correction, but does not write the corrections to the
disk. When you have subdirectories that cannot be
reached, you get the message Cannot CHDIR to
d: pa Ui, tree past this point not processed. If this
occurs, CHKDSK does not free any allocation units
on the disk.

/V to display all files and their paths on the default
or specified drive.

7-48

CHKDSK (Check Disk)
Command

After checking the disk, CHKDSK displays any error
messages, followed by a status report. A complete
listing of error messages can be found in Appendix A
of this book.

CHKDSK does not wait for you to insert a diskette.
It assumes that the diskette you want to check is in
the specified drive. Therefore, on a one-diskette
drive system, it is especially important that the
specified drive is different from the default drive,
unless you are checking the DOS diskette itself.

You should run CHKDSK occasionally for each disk
to ensure the integrity of the file structures.

Notes:

1 . All yes or no (Y/N) prompts from CHKDSK
require you to press Enter after typing y or n, to
prevent accidental changes to your disk.

2. If you specified a filename, the number of
non-contiguous areas occupied by the file will
be reported. Badly fragmented files (many
non-contiguous areas) can cause system
performance to slow down when those files are
accessed, since DOS can not read them
sequentially. You can determine the extent of
file fragmentation by using *.* in the filename
field of the CHKDSK command.

3. If CHKDSK finds lost allocation units (clusters)
on the disk, it asks if you wish to recover the
lost data into files. If you say yes, and the /F
parameter was used, CHKDSK recovers each
chain of lost allocation units into a file whose
name is in the form:

FILEwiwz.CHK

7-49

CHKDSK (Check Disk)
Command

Where nnnn is a sequential number starting with
0000. These files are created in the root
directory of the specified drive. You can then
look at these files to see if they have any useful
information. If not, you can erase them.

4. If you redirect CHKDSK's output to a file, for
example:

A>chkdsk b:>file

It will report errors to that file. In this case, be
sure not to use the /F parameter.

5. CHKDSK does not work on network drives or
drives involved in a substitution (SUBST) or
JOIN.

Example: Following is an example CHKDSK status report:

Volume MYDISK Created AUG 12, 1984 10:00

179712 bytes total disk space

18944 bytes in 3 hidden files

512 bytes in 1 directories

26112 bytes in 4 user files

134144 bytes available on disk

196608 bytes total memory
170736 bytes free

Note that in this status report, three hidden files
were reported. These are the volume label, and the
DOS system files IBMBIO.COM and
IBMDOS.COM, that are hidden from the normal
directory searches. Some application programs also
create hidden files.

7-50

CHKDSK (Check Disk)
Command

The following example produces a CHKDSK status
report for the diskette in drive A.

A>chkdsk a:

The following example produces a CHKDSK status
report for the diskette in drive A and fixes any errors
found in the directory of file allocation table.

A>chkdsk a:/f

The following example produces a CHKDSK status
report for the diskette in drive A and displays all the
files and their paths on drive A.

A>chkdsk a:/v

The following example produces a CHKDSK status
report for disk drive C and lists the filenames on
drive C that contain non-contiguous areas.

A>chkdsk c:*.*

In the previous example, if the files FILE1, FILE3,
and FILE6 contain non-contiguous blocks,
CHKDSK would display these messages:

C:\FILE1

Contains 2 non-contiguous blocks
C:\FILE3

Contains 2 non-contiguous blocks
C:\FILE6

Contains 2 non-contiguous blocks

7-51

CLS (Clear Screen)
Command

Purpose: Clears the display screen.

Format: CLS

Type: Internal External

***

Remarks: This command clears the display on the standard
output device. If screen attributes have been
selected using the "Extended Screen and Keyboard
Control" functions in Chapter 3 of the DOS
Technical Reference, the attributes remain
unchanged.

7-52

COMMAND (Secondary Command

Processor)
Command

Purpose: Use the following command to invoke a secondary
command processor:

Format: COMMAND [d:][path][/F][/C string]

Remarks: Specify the parameters:

[d:][path] is the drive and path that DOS searches to
find the command processor you want to invoke. If
a COMMAND.COM is not found in the specified
directory, DOS searches the path in your
environment for it. COMMAND.COM loads the
transient portion from the file specified in
COMSPEC= as part of its initialization.

/P causes the copy of the new command processor
to become permanent in memory. If you specify /P,
the second command processor does not return to
the primary command processor. You must restart
DOS to remove the second command processor.

[/C string] allows you to pass a string and then
automatically exit back to the primary command
processor after the command is completed.

string is a command that you want to pass to the
command processor. The command is interpreted
and acted upon as if you had typed it at the DOS
prompt. For example, if you type:

A>command /c dir b:

a secondary command processor is loaded, and it
executes the command dir b: and then exits back to
the primary command processor.

7-53

COMMAND (Secondary Command

Processor)

Command

Issuing COMMAND without any parameters causes
a new copy of the command processor to be loaded,
and this new copy will inherit the environment
known to the previous level of the command
processor. If you use the SET command to change
the environment known to the secondary command
processor, that change is known only to the
secondary copy. Exiting back to the primary
command processor causes a resumption of the
environment that the primary command processor
knew before the secondary copy existed.

If you specify the /P and /C parameters together,
then the /P parameter is ignored.

Example: Let's assume that the primary command processor
used the normal DOS prompt of $n$g (which is the
default prompt). If you invoke a secondary copy of
the command processor, the secondary copy
"inherits" that prompt. If you change the
secondary's prompt to something else, and then you
exit back to the primary, the primary's prompt will
still be $n$g.

When a secondary command processor is loaded with
no parameters specified, you can cause it to return to
the previous level of command processor by issuing
the special command EXIT.

Note: Application programmers: please refer to
Chapter 7 of DOS Technical Reference for
additional information.

7-54

COMP (Compare Files)
Command

Purpose: Compares the contents of the first set of specified
files to the contents of the second set of specified
files.

Note: This command compares two sets of files;
the DISKCOMP command compares two entire
diskettes.

Format:

Type:

[d: ][path] COMP [d:][path]\filename[.ext]]
[d: ] [path] [filename[.ext] ]

Internal External

***

Remarks: Specify the parameters:

[d:]\path] before COMP to specify the drive and path
that contains the COMP command file.

[d:][path][filename[.ext]] to specify the first set of
filenames that you want to compare. It is also
referred to as the primary file.

[d:][path][filename[.ext]] to specify the second set of
filenames that you want to compare. It is also
referred to as the secondary file.

Notes:

1 . The files that you compare may be on the same
drive or on different drives. They can also be in
the same directory or different directories.

7-55

COMP (Compare Files)
Command

2. Global filename characters are allowed in both
filespecs, and cause all files matching the first
filespec to be compared with the corresponding
files from the second filespec. Thus, typing:

A>comp a:*. asm b:*.bak

causes each file that has an extension of .ASM
from the current directory of drive A to be
compared with a file of the same name (but with
an extension of .BAK) from the current
directory of drive B.

3. If no parameters are specified with the COMP
command, or if the second parameter is missing,
you are prompted for them. If either parameter
contains only a drive or a path with no filename,
COMP assumes a filename of *. *. You can
enter a complete path with either of the two
filenames.

4. The paths and names of the files being
compared are displayed as the comparing
process proceeds. An error message will follow
if a file matching the second filespec cannot be
found, or the files are different sizes, or a
specified directory path is invalid.

5. It is possible to compare all files in one directory
with all corresponding files in another directory.

6. If no file matches the primary filename, COMP
will prompt you for both the primary and
secondary parameters again.

7. During the comparison, an error message
appears for any location that contains
mismatching information in the two files. The
message indicates the offset into the files of the

7-56

COMP (Compare Files)
Command

mismatching bytes, and the contents of the
bytes themselves (all in hexadecimal), as
follows:

Compare error at OFFSET XXXXXXXX
File 1 = XX
File 2 = XX

In this example, FILE1 is the first filename
typed; FILE2 is the second filename typed.

After ten unequal comparisons, COMP
concludes that further comparing would be
useless; processing ends; and the following
message is displayed:

10 Mismatches - ending compare

After a successful comparison, COMP displays:

Files compare OK

After the comparison of the two files ends,
comparing will proceed with the next pair of
files that match the two filenames, until no more
files can be found that match the first
parameter. Then COMP displays:

Compare more files (Y/N)?_

You now have the option to compare two more
files or to end the comparison. If you want to
compare two more files, enter y. You will be
prompted for new primary and secondary
filenames.

If you want to end COMP processing, type n.
You will return to the DOS prompt.

7-57

COMP (Compare Files)
Command

8. In all compares, COMP looks at the last byte of
the files being compared to assure that it
contains a valid end-of-file mark (Ctrl-Z,
which is the hexadecimal character 1A). If
found, no action is taken by COMP. If the
end-of-file mark is not found, COMP produces
the message:

EOF mark not found

This is done because some products produce
files whose sizes are always recorded in the
directory as a multiple of 128 bytes, even
though the actual usable data in the file is
usually a few bytes less than the directory size.
In this case, COMP may produce compare error
messages when comparing the few bytes beyond
the last real data byte in the last block of 128
bytes (COMP always compares the number of
bytes reflected in the directory). Thus, the EOF
mark not found message indicates that the
compare errors may not have occurred in the
usable data portion of the file.

9. The two sets of files you want to compare can
have the same path and filenames — provided
they are on different drives.

10. If you only specify a drive for the second file, it
is assumed that the second filename is the same
as the first filename.

11. A comparison does not take place if the file
sizes are different.

12. COMP does not wait for you to insert a diskette
containing a file to be compared. Therefore, if a
file to be compared is not on the same diskette
as the COMP command itself, you should type

7-58

COMP (Compare Files)
Command

COMP with no parameters. When COMP
prompts for the filenames, you can insert the
desired diskette and reply with the name of the
file to be compared.

Example: The following example compares all .ASM files on
drive B with the files on drive C with the same
filenames.

A>comp b:*.asm c:

The following example compares all files in the
directory A:\LEVEL1 with corresponding files in
the directory A: \LEVEL2.

A>comp a:\levell a:\level2

7-59

COPY

Command

Purpose: Copies one or more files to the specified disk.

Format: COPY [/ A][/B][d:)[path]filenamelext][/ A][/B]
[d:]\path]\filename[.ext]\[/A][/B][/V]
or

COPY [/A][/B][d:]\path]filename[.ext][/A][/B]
[ + [d:]\path]filename[.ext][/A][/B]...]
[d:][path][filename[.ext]][/A][/B][/V]
or

COPY [/A][/B][d:]\path]filename[.ext][/A][/B]
[+[[„]d:][path]filename[.ext][/A][/B]...]
[d:]\path]\filename[.ext]][/A][/B][/V]

Type: Internal External

***

Remarks: The first file specified is the source file. The second
file specified is the target file. If the second
parameter is a directory {path with no filename), files
are copied into that directory without changing their
names.

Note: COPY is not the same as BACKUP. Use
BACKUP if you want all files including
subdirectories. COPY only copies files from the
current or specified directory.

7-60

COPY

Command

COPY also copies files to the same disk. In this
case, you must give the copies different names unless
different directories are specified; otherwise, the
copy is not permitted. Concatenation (combining of
files) can be performed during the copying process.

You can also use COPY to transfer data between
any of the system devices. An example of how to
copy information that you type at the keyboard to a
file is provided at the end of the description of
COPY Option 2.

Specify /V to cause DOS to verify that the sectors
written on the target diskette are recorded properly.
Although errors in recording data are very rare, this
option has been provided for those of you who wish
to verify that critical data has been correctly
recorded. This option causes the COPY command to
run more slowly, due to the additional overhead of
verification.

The /V parameter provides the same check as does
the VERIFY ON command. /V is redundant if the
VERIFY ON command has been executed
previously. The difference is that /V is effective
only during the duration of the COPY command.
The VERIFY ON command is in effect until
VERIFY OFF is entered.

The parameters /A and /B indicate the amount of
data to be processed by the COPY command. Each
applies to the filespec preceding it and to all
remaining filespecs on the command line until
another /A or /B is encountered. These parameters
have the following meanings:

7-61

COPY

Command

When used with a source filespec:

/A Causes the file to be treated as an ASCII (text)
file. The file's data is copied up to, but not
including, the first end-of-file character
(Ctrl-Z, which is 1AH) found in the file the
remainder of the file is not copied.

/B Causes the entire file (based on the directory
file size) to be copied.

When used with a target filespec:

/A Causes a Ctrl-Z character to be added as the
last character of the file.

/B Causes no end-of-file character (Ctrl-Z) to be
added.

The default values are /A when concatenation is
being performed (see Option 3 below), and /B when
concatenation is not being performed (Options 1 and
2).

Notes:

1 . When copying to or from a reserved device
name, the copy is performed in ASCII (/A)
mode. The first Ctrl-Z character encountered
will end the copy unless /B was specified.

2. If you make a copy of a file that is marked
read-only, the copy will not be marked
read-only.

3. You cannot use COPY to transfer a file using
the COM or AUX serial ports.

7-62

COPY
Command

You can use the global characters ? and * in the
filename and in the extension parameters of both the
source and target files. If you type a ? or * in the
source filespec, the names of the files will be
displayed as the files are being copied. For more
information about global characters, refer to "Global
Filename Characters" in Chapter 2.

The COPY command has three format options:

Option 1 - Copy with Same Name

Use this option to copy a file with the target file
having the same filename and extension as the source
file. For example:

COPY [d:][path]filename[.ext]

COPY [d:][path\filename[.ext] d:\path]

In the first example, we want to copy a file to the
current directory of the default drive. In the second
example, we specify the target drive and/or
directory. In both examples, because we did not
specify the second filename, the copied file will have
the same filename as the source file. Because we did
not specify a name for the second file, the source
drive and the target drive must be different unless
different directories were specified or implied;
otherwise, the copy is not permitted.

For example, assume the default drive is A. The
command:

A>copy b:myprog

7-63

COPY

Command

copies the file MYPROG from drive B to the
current directory on the default drive A, with no
change in the filename. The command:

A>copy *.* b:

copies all the files in the current directory from the
default drive A to drive B, with no change in the
filenames or in the extensions. The filenames are
displayed as the files are copied. This method is very
useful if the files on drive A are fragmented. The
command:

A>copy b:\myprog b:\levell

copies the file MYPROG from the root directory of
drive B to the directory path:

\ level I

on the same drive. The copy has the same filename
as the original file. Note that the above example
assumes that directory \ LEVEL 1 exists on drive B.
If it did not, then the file MYPROG would have
been copied into a file named LEVEL 1 in the root
directory of drive B. In other words, if the second
parameter specifies a directory that exists, the file (or
files) will be placed in that directory, keeping the
same filename. If the second parameter does not
specify a directory that exists, DOS will treat it as a
filename.

7-64

COPY

Command

Option 2 - Copy with Different Name

Use this option when you want the copied file to
have a different name from the file being copied.
For example:

COPY [d:][path]filename[.ext]
\path\filename\_.ext\

COPY [d\]\path]filename[.ext]
d: [path]filename[.ext]

In the first example, we copied a file (first file
specified), and renamed the copy (second file
specified). We did not specify a drive, so the default
drive was used. In the second example, we copied a
file and renamed the copy also. In this example, we
did specify the target drive. Because we changed the
name of the file, the source drive and the target drive
do not have to be different. The current directory
can be the same or different.

For example:

A>copy myprog.abc b:*.xxx

Copies the file MYPROG.ABC from the diskette in
the default drive (drive A in this example) to drive B,
naming the copy MYPROG.XXX. The current
directory of each drive was used.

You can also use reserved device names for the copy
operation. For example:

7-65

COPY

Command

copy con fileA
copy con aux
copy con Iptl
copy filea con
copy fileb aux
copy filec 1 pt2
copy aux lptl
copy aux con

Also, NUL can be used in any variation.

Refer to "Reserved Device Names" in Chapter 2 for
information about system devices.

This example shows how to use COPY to put what
you type from the keyboard into a file:

A>copy con filea

Type a line and press Enter.

Type your next line and press Enter.

Type your last line and press Enter.
Now, press F6 and then press Enter.

When you press F6, and then press Enter, the
COPY operation ends and saves the information you
entered. In this example, the information is saved in
a file named FILEA.

Note: This example assumes that you have not
altered the meaning of F6 through the
"Extended Screen and Keyboard Control"
functions described in Chapter 3 of the DOS
Technical Reference. If you have, then
substitute the key that you have assigned Ctrl-Z
for F6 in this example.

7-66

COPY
Command

Option 3 - Copy and Combine Files

Use this option when you want to combine files
while copying. That is, you can combine two or
more files into one file by adding the additional files
to the end of the first. The date and time recorded in
the result file directory are the current date and time.
The message indicating the number of files copied
refers to the number of result files created.

To combine files, list any number of source files,
separated by plus (+) signs in the COPY command.
Use the following format:

COPY[/A][/B][d:][path]filename[.ext][/A][/B]

[ + [d:][path]filename[.ext][/A][/B]...]

[d:][path][filename[.ext]][/A][/B][/V]

For example:

A>copy a.xyz+b.abc+b:c. txt bigfile.txt

This command creates a new file called
BIGFILE.TXT on the default drive. The
combination of A.XYZ, B.ABC, and B:C.TXT is put
into BIGFILE.TXT.

If you do not specify a result filename, the additional
files are added to the end of the first file, leaving the
result in the first file. For example,

A>copy a.asm+b.asm

7-67

COPY

Command

In this case, COPY appends B.ASM to the end of
A.ASM and leaves the result in A.ASM.

Note: Combining files is normally performed in
text (or ASCII) mode. That is, the first Ctrl-Z
(hex 1A) character in the file is interpreted as
an end-of-file mark. To combine binary files,
use the /B parameter to force COPY to use the
physical end-of-file (the file length shown in
the DIR command).

You can also combine ASCII and binary files by
using the following parameters:

. ASCII - /A

• Binary - /B

For example,

A>copy a.xyz+b.com/b+b:c. txt/a bigfile.txt

A /A or /B takes effect on the file it is placed after,
and it applies to all subsequent files on the command
line until another /A or /B is found. A /A or /B on
the result file causes a Ctri-Z to be added (/A), or
not to be added (/B), as the last character in the
result file.

You can use the global characters ? and * in the
filenames of both the files to be combined and the
result file. For example:

A>copy *. 1 st combin.prn

In this example, all files matching *.LST are
combined into one file called COMBIN.PRN:

A>copy *.lst+*.ref combin.prn

7-68

COPY

Command

This example combines all files matching *.LST and
then all files matching *.REF into one file called
COMBIN.PRN:

A>copy *.lst+*.ref *.prn

In this example, each file matching *.LST is
combined with the corresponding .REF file, with the
result having the same name but with extension
.PRN. Thus, a file FILE1.LST would be combined
with FILE1.REF to form FILE1.PRN; XYZ.LST
would be combined with XYZ.REF to form
XYZ.PRN; etc. Note that in this case (when
multiple files are to be created), only one file from
each of the source filespecs is used to create a given
target file.

For more information about global characters, refer
to "Global Filename Characters" in Chapter 2.

It is easy to enter a COPY command to combine files
where one of the source files is the same as the
target, yet this often cannot be detected. For
example:

A>copy *.lst all .1st

This would produce an error if ALL.LST already
existed. The error would not be detected, however,
until it was time for ALL.LST to be appended; by
this time, ALL.LST could already have been altered.

COPY handles this situation as follows: As each
input file is found, its name is compared with the
target filename. If the names are the same, that one
input file is skipped, and the following message is
displayed on the screen:

Content of destination lost before copy

7-69

COPY
Command

Further copying proceeds normally. This allows
summing files, with a command like:

A>copy all .1st + *.lst

This command appends all .LST files, except
ALL.LST itself, to ALL.LST. In this case, the error
message is suppressed, because this is a true physical
append to ALL.LST.

The following are special cases. Remember to use
the /B parameter whenever you use the plus (+) sign
with non- ASCII files:

A>copy b:xyz.asm+

This command copies the file XYZ.ASM to the
default drive and gives it a new date and time. To
simply change the date and time, leaving the file in
place, you can use the following command:

A>copy b:xyz.asm+, , b:

In these special cases, if global filename characters
are used in the filename or extension, then all of the
matching files will be appended together into the first
filename that matches. Thus, the command:

A>copy b :*.*+, , b:

will not update the dates and times of all files on
drive B, but will append all of drive B's files together
into a single file that will replace the first file found
on drive B.

7-70

COPY

Command

Note: When combining files, COPY considers
the copying process to be successful if at least
one, but not necessarily all, of the named source
files is found. If none of the source files can be
found, you receive the message

file(s) copied

7-71

CTT Y (Change Console)
Command

Purpose: Changes the standard input and output console to an
auxiliary console, or restores the keyboard and
screen as the standard input and output devices.

Format: CTTY device-name

Type: Internal External

***

Remarks: Specify the parameter:

device-name to define the device to use as the
primary console. Specify AUX, COM1, or COM2
to use that device as the primary console. Specify
CON to reset the primary standard input and output
devices to the primary console.

Notes:

The CTTY command accepts the name of any
character-oriented device to allow you to install
your own device drivers, and to specify their
device names. You must be certain that the
named device is capable of both input and
output operations. For example, you should not
specify the name of a printer, because DOS will
attempt to read from that device.

The CTTY command is effective only for
programs that use DOS function calls. Other
programs, such as BASIC (that do not use DOS
function calls), are not able to use the CTTY
command to change the standard input and
output devices. Therefore if you load BASIC

7-72

CTT Y (Change Console)

Command

while you are using CTTY, the standard input
and output console are reset to the keyboard

and screen.

Example: The following example causes DOS to use the AUX
device for its standard input and output operations:

A>ctty aux

The following example reverses the previous
assignment, causing DOS to switch back to the
standard screen and keyboard for its operations:

A>ctty con

7-73

DATE
Command

Purpose: Use to enter or change the date known to DOS. The
date is recorded in the directory when you create or
change a file.

Format: DATE [mm-dd-yy] \ [dd-mm-yy] \ [yy-mm-dd]

Type: Internal External

***

Remarks: Specify the parameters:

mm to specify the month. Type one or two numbers
from 1 to 1 2 for the month.

dd to specify the date. Type one or two numbers
from 1 to 3 1 for the day.

yy to specify the year. Type two numbers between
80 and 99 or four numbers between 1980 and 1999
for the year.

Notes:

1 . If you type DATE with no parameters, the
following prompt is displayed:

Current date is day mm-dd-yy
Enter new date (mm-dd-yy) :__

The format for the date (mm-dd-yy or
dd-mm-yy or yy-mm-dd) depends on the
country you selected with the SELECT
command. You also can change the format for
the date by creating a CONFIG.SYS file that

7-74

DATE
Command

contains the COUNTRY command. Refer to
Chapter 4, "Configuring Your System" for
more information on the COUNTRY command.

2. Separate the parts of the date with a dash (-), a
slash (/) or a period (.). For example, to set the
date to September 23, 1984, type:

9-23-84

or
9/23/84

or
9.23.84

3. If you type a valid date, the new date is
accepted and the DOS prompt is displayed. If
the date is invalid, the following prompt is
displayed:

Invalid date

Enter new date (mm-dd-yy) :_

4. DOS displays the day of the week (Tue for
example) for information purposes only. Do not
include the day of the week when you type the
date.

5 . You can change the date from the standard
input device or from a batch file. Remember,
when you start the system, it does not prompt
you for the date if you use an
AUTOEXEC.BAT file. You can include a
DATE command in that file. For more
information about the AUTOEXEC.BAT file,
refer to "Batch File Commands" in this chapter.

7-75

DATE

Command

6. To leave the date as-is, press Enter.

7. If you are using an IBM Personal Computer AT,
typing a new date does not change the system
clock. Refer to your GTO for information on
the system clock.

8. Leaving your computer on for more than 24
hours with no activity may cause the date to be
incorrectly updated.

Example: The following example changes the date to July 24,
1984.

A>date

Current date is Mon 1-18-1984

Enter new date: 7/24/84

7-76

DEL (Delete)
Command

Purpose: Deletes the specified file.
Format: DEL [d:][path]filename[.ext]
Type: Internal External

***

Remarks: Specify the parameters:

[d:] to specify the drive that contains the file you
want to delete.

[path] to specify the directory path that contains the
file you want to delete.

filename[.ext\ to specify the name of the file you
want to delete.

Notes:

1 . If the drive specifier is not specified, the default
drive is assumed.

2. If the path is not specified the current directory
is assumed.

3. If the filename is not specified, *.* is assumed
and all files are deleted.

4. You can use the global filename characters ?
and * in the filename and extension. However,
use global filename characters with caution
because multiple files can be deleted with a
single command.

7-77

DEL (Delete)
Command

5. If you use the filespec *.* to delete all the files
on a disk, the following message is displayed to
verify that you actually want to delete all files:

Are you sure (Y/N)?

Type y (yes) and press Enter if you do want to
delete all the files on the disk.

Type n (no) and press Enter if you do not want
to erase all files on the disk.

6. You cannot delete files that are marked as
read-only.

7. You cannot use DEL to delete a subdirectory.
To delete a subdirectory, use the RMDIR
(remove directory) command.

8. Extra care should be exercised when using DEL
after using ASSIGN, JOIN, or SUBST.

Example: The following example deletes the file name
FILE. BAT from the diskette in drive A.

A>del a: file. bat

The following example deletes all files from the
directory \ LEVEL 1 on drive C.

A>del c:\levell

7-78

DIR (Directory)
Command

Purpose: Lists either all the directory entries, or only those for
specified files.

Note: Directory entries for hidden system files
such as IBMBIO.COM and IBMDOS.COM are
not listed, even if present.

Format: DIR [d:][path]\filename[.ext]][/F][/W]

Type: Internal External

Remarks: Specify the parameters:

[d:][path][filename[.ext]] to specify the file whose
directory you want to list.

/P to pause the display when the screen is full. The
following prompt is displayed:

Strike a key when ready . . .

To continue press any key.

/W to display the information in a wide display
format. Only the filenames and directory names are
shown. This parameter is only recommended for
80-column displays.

Notes:

1 . The information provided in the directory listing
includes the volume identification and the
amount of free space left on the disk. The
freespace amount is rounded up to the nearest

7-79

DIR (Directory)
Command

1024K bytes. The display line for each file
includes its size in decimal bytes and the date
and time the file was last written to.

Note: If you set the COUNTRY
configuration command to a country other
than U.S., the date and time format
displayed may be different. The examples
in this section show the date displayed for
the U.S. date and time format.

2. Entries that name other directories are clearly
identified with <DIR> in the file size field.

3. You can use the global characters ? and * in the
filename and extension parameters. For more
information about the global characters, refer to
"Global Filename Characters" in Chapter 2.

4. If you do not specify a filename extension, the
default is *.

5. To display the directory entry for a file that does
not have an extension, type the filename
followed by a period. In this case, the .ext does
not default to *.

6. The DIR command has two format options (the
/P and /W parameters may be used with either
option) :

• List All Files
or

• List Selected Files

7-80

Example:

DIR (Directory)
Command

Option 1 - List All Files

The following example lists all the directory entries
on the default drive.

A>dir

The directory may look like this:

Volume

drive A is MYDISK

Directc

iry

A:\

FILE1

10368

7-20-83

12:

:13p

FILE3

1613

5-27-83

12:

:14p

8-17-82

10:

:59a

LEVEL2

<DIR>

9-09-82

12:

:10p

FILE1

2288

9-02-82

12:

:25p

5 File(s) 141312 bytes free

The following example lists all the directory entries
for current directory of drive C.

A>dir c:

The following example lists all the directory entries
for the directory path \LEVEL2:

A>dir \ level 2

The screen will look like this:

7-81

DIR (Directory)
Command

Volume in drive A is MYDISK
Directory of A:\LEVEL2

<DIR> 9-09-84 l:30p

<DIR> 9-09-84 2:45p

MYPROG COM 2463 7-30-84 8:55a

3 File(s) 141312 bytes free

Note that all files in directory LEVEL2 have been
listed, including the two special entries found in all
subdirectories. The entry marked with a single
period denotes the directory being listed (LEVEL2),
and the double period denotes this directory's parent
directory (in this case, the root directory). Thus, if
your current directory is LEVEL2 and you wish to
see the files in its parent directory, you can enter:

A > rj j r

Option 2 - List Selected Files

The following example lists the directory entry of the
file named FILE3.A in the current directory of the
default drive.

A>dir file3.a

the screen may look like this:

Volume in drive A is MYDISK
Directory of A: \

FILE3 A 1613 5-27-84 12:14p

1 File(s) 141312 bytes free

7-82

DIR (Directory)
Command

If you type:

A>dir *.a

the screen may look like this:

Volume in drive A is MYDISK
Directory of A: \

FILE1 A 10368 7-20-84 12:13p

FILE3 A 1613 5-27-84 12:14p

2 File(s) 141312 bytes free

If you type:

A>dir filel

the screen may look like this (omission of .ext
defaults to *):

Volume in drive A is MYDISK
Directory of A: \

FILE1 A 10368 7-20-84 12:13p

FILE1 2288 9-02-84 12:25p

2 File(s) 141312 bytes free

To display only the entry for a file that has no
extension, enter the filename followed by a period.
In this case, the .ext does not default to *. For
example,

A>dir filel .

7-83

DISKCOMP (Compare Diskettes Only)
Command

Purpose: Compares the contents of the diskette in the first
specified drive to the contents of the diskette in the
second specified drive.

Notes:

1 . This command is used only for comparing
diskettes. If a fixed disk drive letter is specified,
an error message is displayed.

2. This command compares two entire diskettes', the
COMP command compares two files.

Format: [J:][/?a//z]DISKCOMP [d: [d:]] [/l] [/8]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before DISKCOMP to specify the drive
and path that contains the DISKCOMP command
file.

[d:] to specify the source drive.

[d:] to specify the target drive.

/I to compare only the first side of the diskettes,
even if the diskettes and drives are dual-sided.

/8 to compare only 8 sectors per track, even if the
first diskette contains 9/15 sectors per track.

7-84

DISKCOMP (Compare Diskettes Only)

Command

You can specify the same drive or different drives in
this command. If you specify the same drive, a
one-drive comparison is performed. You are
prompted to insert the diskettes at the appropriate
time. DISKCOMP waits for you to press any key
before it continues.

DISKCOMP compares all tracks on a
track-for-track basis and issues a message if the
tracks are not equal. The message indicates the track
number and the side (0 or 1) where the mismatch
was found.

After completing the comparison, DISKCOMP
prompts:

Compare more diskettes (Y/N)?_

If you type y, the next comparison is done on the
same drives that you originally specified, after you
receive prompts to insert the proper diskettes.

To end the command, type n. If the following
message is displayed, insert the DOS diskette in drive
x and press any key when ready.

Insert disk with \C0MMAND.C0M in drive A
and strike any key when ready

Notes:

If you omit both parameters, a one-drive
comparison is performed on the default drive.

If you omit the second parameter, the default
drive is used as the secondary drive.

On a one-drive system, all prompts are for drive
A, regardless of any drive specifiers entered.

7-85

DISKCOMP (Compare Diskettes Only)
Command

4. DISKCOMP usually does not issue a Diskettes
compare OK message if you try to compare a
backup diskette created by the COPY command
with the diskette you copied from. The COPY
operation produces a copy that contains the
same information, but may place the
information at different locations on the target
diskette from those locations used on the source
diskette. In this case, you should use the COMP
command to compare individual files on the
diskettes.

5. If a diskette error occurs while DISKCOMP is
reading the diskette, a message is produced that
indicates where (track and side) the error
occurred. Then DISKCOMP continues to
compare the rest of the diskette. Because the
remainder of the data to be compared cannot be
read correctly from the indicated track and side,
you can expect to receive a Compare error
message.

6. DISKCOMP automatically determines the
number of sides and sectors per track to be
compared, based on the diskette that is to be
read first (the first drive parameter entered).

If the first diskette or drive can be read on only
one side, or if the /l parameter is used, only the
first side is read from both diskettes. If the first
diskette contains 9 sectors per track, then
DISKCOMP will compare 9 sectors per track
unless you used the /8 parameter. If the first
diskette contains 1 5 sectors per track, then
DISKCOMP will compare 15 sectors per track.
If the first drive and diskette are double-sided,
and /l is not snecified. a two-sided comnarison

7-86

DISKCOMP (Compare Diskettes Only)

Command

is done. In this case an error message is
produced if either the second drive or the
diskette is a single-sided diskette.

7. The source and target drives cannot be virtual
drives, such as those created by the SUBST
command.

8. DISKCOMP does not recognize assigned drives.

9. DISKCOMP should not be used while a JOIN is
in effect.

10. DISKCOMP does not work on network drives.

7-87

DISKCOMP (Compare Diskettes Only)
Command

DISKCOMP Compatibility

This section describes the possible diskette
combinations that you may use with DISKCOMP:

If your computer has single-sided diskette drives, you
can use DISKCOMP to compare:

• A single-sided diskette to a single-sided diskette

If your computer has double-sided diskette drives,
you can use DISKCOMP to compare:

• A single-sided diskette to a single-sided diskette

• A double-sided diskette to a double-sided
diskette

If your computer has high-capacity diskette drives,
you can use DISKCOMP to compare:

• A single-sided diskette to a single-sided diskette

• A double-sided diskette to a double-sided
diskette

• A high-capacity diskette to a high-capacity
diskette

No other combinations are allowed. If you specify
an invalid combination, the following message is
displayed:

Drive types (double, single-sided) or
diskette types not compatible

7-88

DISKCOMP (Compare Diskettes Only)

Command

Example: The following example compares the diskette in drive
A to the diskette in drive B.

A>diskcomp a: b:

The following example compares the first diskette in
drive A to the second diskette in drive A. Notice,
that by not specifying the source and target drive, a
one-drive compare is performed. You have to
switch diskettes as prompted.

A>diskcomp

The following example compares the first diskette in
drive B to the second diskette in drive A.

A>diskcomp b:

7-89

DISKCOPY (Copy Diskettes Only)
Command

Purpose: Copies the contents of the diskette in the source

drive to the diskette in the target drive. The target
diskette is formatted if necessary, during the copy.

Notes:

1 . This command is used only for copying
diskettes. If a fixed disk drive letter is specified,
an error message is displayed.

2. This command copies two entire diskettes; the
COPY command copies two files.

Format: [rf:][paf/z]DISKCOPY [d: [d:]][/l]
Type: Internal External

Remarks: Specify the parameters:

[d:][path] before DISKCOPY to specify the drive
and path that contains the DISKCOPY command
file.

[d:] to specify the source drive.

[d\] to specify the target drive.

/I to copy only the first side of the diskette,
regardless of the diskette or drive type.

You can specify the same drives or different drives.
If the drives are the same, a one-drive copy operation

7-90

DISKCOPY (Copy Diskettes Only)

Command

is performed. You are prompted to insert the
diskettes at the appropriate times. DISKCOPY waits
for you to press any key before continuing.

After copying, DISKCOPY prompts:

Copy another (Y/N)?_

If you type y, the next copy is done on the same
drives that you originally specified, after you are
prompted to insert the proper diskettes.

To end the command, type n. If the following
message is displayed, insert the DOS diskette in drive
x and press any key when ready.

Insert diskette with \ COMMAND. COM in drive A
and strike any key when ready

Notes:

1 . If the target diskette has not been formatted
with the same number of sides and sectors per
track as the source diskette, DISKCOPY will
format the target diskette during the copy
operation.

2. If you omit both drive parameters, a one-drive
copy operation is performed on the default
drive.

3. If you omit the second parameter, the default
drive is used as the target drive.

4. If you omit the second parameter and you
specify the default drive as the source drive, a
one-drive copy operation is performed.

7-91

DISKCOP Y (Copy Diskettes Only)
Command

5. On a one-drive system, all prompts will be for
drive A, regardless of any drive letter you may
enter.

6. Diskettes that have had a lot of file creation and
deletion activity become fragmented, because
diskette space is not allocated sequentially. The
first free sector found is the next sector
allocated, regardless of its location on the
diskette.

A fragmented diskette can cause degraded
performance due to excessive head movement
and rotational delays involved in finding,
reading, or writing a file.

If this is the case, it is recommended that you
use the COPY command, instead of
DISKCOPY, to eliminate the fragmentation.

For example, place a freshly formatted diskette
in drive B, and the diskette you wish to copy in
drive A. The command:

A>copy a:*.* b:

copies all the files from the diskette in drive A
to the diskette in drive B. The resultant files (in
drive B) are now copied sequentially. You
should get better performance when you use
these files from now on.

7 . You can run DISKCOMP after a successful
DISKCOPY to verify that the diskettes are
identical.

8. If disk errors are encountered on either diskette,
DISKCOPY indicates the drive, track, and side
in error and proceeds with the copy. In this

7-92

DISKCOPY (Copy Diskettes Only)

Command

case, the target diskette (copy) may or may not
be usable, depending on whether the affected
diskette location was to contain valid data.

9. DISKCOPY automatically determines the
number of sides and sectors per track to copy,
based on the source drive and diskette. If only
the first side of the source diskette can be read,
then only the first side can be copied. If the
source drive and diskette are double-sided, both
sides can be copied (unless you override it with
the /l parameter). In this case, if the target
drive is single-sided, an error message will
indicate that the drives are incompatible.

If the source diskette has ever been physically
formatted with 9 sectors per track, then all 9
sectors on each track will be copied.

10. The source and target drive cannot be a virtual
drive, such as those created by the SUBST
command.

1 1 . DISKCOPY does not recognize an assigned
drive.

12. Double-sided diskettes written on in a
high-capacity diskette drive will not be reliably
read in a single- or double-sided diskette drive.

13. DISKCOPY should not be used while a JOIN is
in effect.

14. DISKCOPY does not work with network drives.

7-93

DISKCOPY (Copy Diskettes Only)
Command

DISKCOPY Compatibility

This section describes the possible diskette
combinations that you may use with DISKCOPY:

If your computer has single-sided diskette drives, you
can use DISKCOPY to copy:

• a single-sided diskette to a single-sided diskette

If your computer has double-sided diskette drives,
you can use DISKCOPY to copy:

• a single-sided diskette to a single-sided diskette

• a double-sided diskette to a double-sided
diskette

If your computer has high-capacity diskette drives,
you can use DISKCOPY to copy:

• a single-sided diskette to a single-sided diskette*

• a double-sided diskette to a double-sided
diskette*

• a high-capacity diskette to a high-capacity
diskette

• Caution: You may not be able to reliably read these
diskette types in a single- or double-sided diskette
drive.

7-94

DISKCOPY (Copy Diskettes Only)

Command

No other diskette combinations are allowed. If you
specify an invalid combination, the following
message is displayed:

Drive types (double- or single-sided) or
diskette types not compatible

If you want to copy the contents of a double-sided
diskette onto a high-capacity diskette, use the COPY
*.* command. Refer to the COPY command in this
chapter for more information.

Example: The following example copies the diskette in drive A
to the diskette in drive B.

A>diskcopy a: b:

The following example copies the source diskette in
drive A to the target diskette in drive A. Notice, that
by not specif ing the source and target drive, a
one-drive copy is performed. You must switch
diskettes as prompted.

A>diskcopy

The following example copies the source diskette in
drive B to the target diskette in drive B. Notice that
by not specif ing the source and target drive, a
one-drive copy is performed. You must switch
diskettes as prompted.

B>diskcopy

7-95

ERASE

Command

Purpose: Erases the specified file.
Format: ERASE [d:]\path]filename[.ext]

Type: Internal External

***

Remarks: Specify the parameters:

[d:] to specify the drive that contains the file you
want to erase.

[path] to specify the directory path that contains the
file you want to erase.

filename[.ext] to specify the name of the file you
want to erase.

Notes:

1 . If the drive specifier is not specified, the default
drive is assumed.

2. If the path is not specified the current directory
is assumed.

3. If the filename is not specified, *.* is assumed
and all files are erased.

4. You can use the global filename characters ?
and * in the filename and extension. However,
use global filename characters with caution
because multiple files can be erased with a single
command.

7-96

ERASE
Command

5. The operating system files IBMBIO.COM and
IBMDOS.COM cannot be erased.

6. If you use the filespec *.* to erase all of the files
on a disk, the following message is displayed to
verify that you actually want to erase all files:

Are you sure (Y/N)?

Type y (yes) and press Enter if you do want to
erase all the files on the disk.

Type n (no) and press Enter if you do not want
to erase all files on the disk.

7. You cannot erase files that are marked as
read-only.

8. You cannot use ERASE to erase a subdirectory.
To delete a subdirectory you need to use the
RMDIR (remove directory) command.

9. Extra care should be exercised when using
ERASE after using ASSIGN, JOIN, or SUBST.

Example: The following example erases the file name
FILE.BAT from the diskette in drive A.

A>erase a: file. bat

The following example erases all files from the
directory \ LEVEL 1 on drive C.

A>erase c: \levell

7-97

EXE2BIN

Command

Purpose: Converts .EXE files to .COM or .BIN files.

Format: [d:][path]EXE2BYN [d:][path]fi!ename[.exi\
[d: ] [path] \filename\_ . ext] ]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before EXE2BIN to specify the drive
specifier and path that contains the EXE2BIN
command file.

[d:\path\filename\ext] to specify the input file. If
you do not specify:

[d\] the default drive is assumed

[path] the current directory is assumed

[.ext] .EXE is assumed

[d:][path]filename .[ext] to specify the output file. If
you do not specify:

[d\] the drive of the input file is assumed

[path] the current directory is assumed

filename the input filename is assumed

[.ext] .BIN is assumed

7-98

EXE2BIN

Command

The input file is converted to .COM file format
(memory image of the program) and placed in the
output file.

The input must be in valid .EXE format as produced
by the Linker. The resident, or actual code and data,
part of the file must be less than 64K. There must be
no STACK segment.

Two kinds of conversions are possible, depending on
the specified initial CS:IP:

• If CS: IP is not specified in the program (the
.EXE file contains 0:0), a pure binary
conversion is assumed. If segment fixups are
necessary (the program contains instructions
requiring segment relocation), you are prompted
for the fixup value. This value is the absolute
segment at which the program is to be loaded.

In this case, the resultant program is usable only
when loaded at the absolute memory address
specified by a user application. The DOS
command processor will not be capable of
properly loading the program.

• If CS:IP is specified as 0000: 100H, it is
assumed that the file is to be run as a .COM file,
with the location pointer set at 100H by the
assembler statement ORG. No segment fixups
are allowed, as .COM files must be segment
relocatable, that is, they must assume the entry
conditions explained in Chapters 5 of the DOS
Technical Reference. Once the conversion is
complete, you may rename the resultant file to a
.COM extension. Then, the command processor
is capable of loading and executing the program
in the same manner as the .COM programs
supplied on your DOS diskette.

7-99

EXE2BIN
Command

If CS:IP does not meet one of these criteria, or if it
meets the .COM file criterion but has segment
fixups, the following message is displayed:

File cannot be converted

This message is also displayed if the file is not a
valid .EXE file.

To produce standard .COM files with the assembler,
you must both use the assembler statement ORG to
set the location pointer of the file at 100H and
specify the first location as the start address. (This is
done in the END statement.) Also, the program
must not use references that are defined only in
other segments. For example, with the IBM Personal
Computer MACRO Assembler:

ORG 1
START:

END START

EXE2BIN resides on your DOS Supplemental
Program diskette.

7-100

FDISK

Command

See Chapter 3, "Preparing Your Fixed Disk."

7-101

FIND Filter
Command

Purpose: Sends all lines from the specified filenames that

contain the specified string to the standard output
device.

Format: [d:][path]FIND

[/V]UC][/N]"string"[[d:]\path]filename[.ext]...]

Type: Internal External

Remarks: Specify the parameters:

[d:][path] before FIND to specify the drive specifier
and path that contains the FIND command file.

/V to display all lines not containing the string.

/C to display a count of the number of lines
containing string. If /C is specified with /V or /N,
then FIND ignores /V and /N.

/N to display the relative line number of each
matching line ahead of the line from the file.

Enclose the string in double quotes ("). Two quotes
in succession are taken as a single quote. An
uppercase string does not match a lowercase string.

Global filename characters are not allowed in the
filenames or extensions.

Example: The following example displays all lines from

BOOKl.TXT, BOOK2.TXT, and BOOK3 (in that
order) that contain the string "Fool's Paradise."

A>find "Fool's Paradise" bookl.txt book2.txt book3

7-102

FIND Filter
Command

The following example displays the names of all files
in the current directory of drive B that do not contain
the string "DAT."

A>dir b: \ find /v "DAT"

The following example displays all the subdirectory
entries in the current directory (redirects the output
of the DIR command to the FIND filter and then
displays the directory entries that contain DIR).

A>dir I find "<DIR>"

For the following examples, assume the file PROG
contains the following lines:

This is a
beautiful
day for a picnic.

The following example displays the lines in the file
PROG that do not contain the string "f."

A>find /v"f"prog
The result is:

a:prog

This is a

7-103

FIND Filter
Command

The following example displays the relative line
number of the lines that contain the string "f."

A>find /n"f"prog

The result is:

a:prog

[2]beautiful

[3]day for a picnic.

The following example displays a count of the
number of lines in the file PROG that contain the
string "a."

A>find /c" a "a: prog
The result is:
a : prog : 2

7-104

FORMAT
Command

Purpose: Initializes the disk in the designated or default drive
to a recording format acceptable to DOS; analyzes
the entire disk for any defective tracks; and prepares
the disk to accept DOS files by initializing the
directory, File Allocation Table, and system loader.

CAUTION

Please note that formatting destroys all data on
the disk. Because of this, you should be very
careful before you decide to format any disk,
particularly a fixed disk. If you attempt to
format your fixed disk, please note that the
entire contents of any previously created DOS
partition, including all subdirectories and their
contents, are destroyed. If you are not certain
which drive is the default drive, do NOT enter
FORMAT without a drive letter. If you do not
specify a drive letter, you could unintentionally
destroy all of the data on whatever disk happens
to be the default. It's safer to specify a drive
letter.

Format: [d:][path]FORMAT [</:][/S][/l][/8][/V][/B][/4]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before FORMAT to specify the drive
specifier and path that contains the FORMAT
command file.

[d:] to specify the drive that contains the disk you
want to format.

7-105

FORMAT

Command

/S to copy the operating system files from the DOS
diskette in the default drive to the new disk in the
following order:

IBMBI0.COM
IBMD0S.COM
C0MMAND.COM

If the system does not reside on the default drive,
and the default drive is non-removable, FORMAT
prompts you to put a system diskette in diskette drive
A. If the system is not on the default drive and the
default drive is removable, FORMAT prompts you
to insert a system diskette in the default drive.

/I to format a diskette for single-sided use regardless
of the drive type.

/8 to format a diskette for 8 sectors per track.
FORMAT defaults to 9/15 sectors per track usage if
you do not specify /8. Note that format always
creates 9/15 physical sectors on each diskette track,
but that it instructs DOS to use only 8 sectors per
track if you use the /8 parameter.

/V to give the disk a volume label. We strongly
recommend that you use the /V parameter. This
uniquely identifies each disk.

The volume label cannot be used in place of
filenames as input to any of the DOS commands. The
volume label is for your use in keeping track of your
disks.

/B to format a diskette for 8 sectors per track
diskette with space allocated for the IBMBIO.COM
and IBMDOS.COM system modules. It does not
place the system modules or the command processor
on the diskette. This parameter is used to create a

7-106

FORMAT

Command

diskette on which any version of DOS can be placed
through that version's SYS command. If the /B
parameter is not used, only DOS Version 3.10 can be
placed on the diskette through the SYS command.

/4 to format a double-sided diskette in a
high-capacity drive.

CAUTION

This parameter is intended to allow use of
double-sided diskettes in high-capacity drives.
However, the diskettes formatted with the /4
parameter specified may not be reliably read or
written in a single- or double-sided drive.

The following table shows which parameters are
valid for certain diskette types:

Disk Type

Parameters Allowed

320KB

/S,/V, /l,/8,/B,/4

1.2MB

/s,/v

fixed disk

/s,/v

7-107

FORMAT

Command

Notes:

1 . All new diskettes and fixed disks must be
formatted before they can be used by DOS.
Refer to Chapter 3 for more information before
formatting your fixed disk.

2. A fixed disk must also be formatted again if you
change the size of its DOS partition through the
FDISK command.

3. Formatting destroys any previously existing data
on the disk.

4. During the formatting process, any defective
tracks are marked as reserved to prevent the
tracks from being allocated to a data file.

5. Directory entries for IBMBIO.COM and
IBMDOS.COM are marked as hidden files, and
therefore, they do not appear in any directory
searches — including the DIR command.

6. FORMAT will prompt you to enter a volume
label (volume identification) if you have used
the /V parameter. The label can consist of from
1 to 1 1 characters. All characters acceptable in
filenames are acceptable in the volume label.
Unlike filenames, however, the volume label
does not contain a period between the eighth
and ninth characters.

You can add or change a volume label using the
LABEL commmand. For more information
refer to the LABEL command in this chapter.

7-108

FORMAT
Command

7. FORMAT produces a status report, that
indicates:

• Total disk space

• Space marked as defective

• Space currently allocated to the DOS
system files (when /S is used)

• Amount of space available for your files

8. FORMAT determines the target drive type and
formats the disk or diskette accordingly. For
diskettes, if the diskette can be successfully read
and written on only one side, the diskette is
formatted for single-sided use, 8 sectors per
track; it can be used in either type of drive. If
the target drive is double-sided and you do not
use the /l parameter, the diskette is formatted
for double-sided use; it will not be usable in a
single-sided drive.

9. Fixed disks are already physically formatted
(proper recording format) when shipped by
IBM. When formatting a fixed disk, FORMAT
checks all locations within the DOS partition,
but does not physically format them again.

10. If the /S parameter is used and the system has
insufficient available memory for FORMAT to
load all three system modules, it will load as
many modules as it can, format the target disk,
and write the modules that are in memory. It
must then read the remaining modules from the
source disk so they can be placed on the target
disk. If the source diskette has been removed

7-109

FORMAT
Command

from the drive, an appropriate message will
prompt you to reinsert it before FORMAT can
continue.

11. The parameters /8 and /V cannot be specified
with the /B parameter.

12. If you specify the /S parameter, the system files
are copied from the default drive. If the default
drive is a fixed disk drive that does not contain
the system files, then you are prompted to insert
the DOS diskette in drive A.

13. FORMAT ignores any drive reassignments
(ASSIGN).

14. FORMAT should not be used with drives
involved in a JOIN or substitution (SUBST).

15. FORMAT does not work on network drives.

FORMAT Compatibility

The following table shows the possible diskette
combinations that may be used with FORMAT:

Drive
Type

Diskette Type

single
sided

single-sided diskettes

double
sided

single-sided or double-sided
diskettes

7-110

FORMAT
Command

Drive
Type

Diskette Type

high
capacity

single-sided*, double-sided* or
high-capacity diskettes

* To format a single-sided or double-sided diskette
in a high-capacity drive, refer to the FORMAT/4
command in this chapter.

No other combinations are allowed.

Example: By issuing the following command, the diskette in
drive B is formatted and the operating system files
are also copied:

A>format b:/s/v

The system displays the following message:

Insert new diskette for drive B:
and strike ENTER when ready

After you insert the appropriate diskette and press
ENTER, the system displays this message:

Formatting . . .

while the diskette formatting is taking place.

Once the formatting is complete, the system displays
this message:

7-111

FORMAT
Command

Formatting. .. Format complete
System transferred

Volume label (11 character, ENTER for none)? mydisk

xxxxxx bytes total disk space

xxxxx bytes used by system
xxxxxx bytes available on disk

Format another (Y/N)?n

In the above example, note that MYDISK was typed
as the volume label.

Type y and press Enter to format another diskette.

Type n and press Enter to end the FORMAT
program.

When you format a fixed disk, you will see the
following message instead of the prompt to insert a
diskette:

Warning, All Data on Non-Removable
Disk Drive x: Will Be Lost!
Proceed with Format (Y/N)?

The x is replaced by the drive letter you typed. If
you want to format your fixed disk, type y and press
Enter. If you do not want to format your fixed disk,
type n and press Enter.

Fixed disk formatting can take several minutes
because of the large size that can be allocated to
DOS, so don't be alarmed if it takes some time
before you are prompted for the volume label. You
can tell that FORMAT is working by noting that
your fixed disk drive light is on.

7-112

GRAFTABL (Load Graphics Table)

Command

Purpose: Loads a table of additional character data for the
color/graphics adapter into memory.

Format: [d:]\path]GRAFTASL

Type: Internal External

***

Remarks: Specify the parameters:

[d:]\path] before GRAFTABL to specify the drive
and path that contains the GRAFTABL command
file.

Use GRAFTABL to display foreign language
characters when in graphics mode on the
color/ graphics adapter. GRAFTABL loads a table
of data in memory which defines these additional
characters for the color/ graphics adapter to use.
This allows the ASCII characters 128 thru 255 to be
displayed when using the Color/Graphics adapter in
graphics mode. This command increases the resident
size of DOS in memory.

• After loading the character table and initializing
the interrupt vector, GRAFTABL responds with
the message:

GRAPHICS CHARACTERS LOADED

and then the DOS prompt is displayed.

7-113

GRAFTABL (Load Graphics Table)
Command

• GRAFTABL should only be invoked once each
time DOS is started. If you try to load
GRAPHICS once it is already loaded, the
following message is displayed:

GRAPHICS CHARACTERS ALREADY LOADED

Example: The following example loads the table of graphics
characters:

A>graftabl

The system now supports display of ASCII
characters 128 through 255 in the graphics mode on
the Color/Graphics Adapter.

7-114

GRAPHICS (Screen Print)

Command

Purpose: Allows the contents of a graphics display screen to
be printed on an IBM Personal Computer Printer
when using a color/graphics monitor adapter.

Format: [d:][pat h]GRAPHlCS [printer type] [/R][/B]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before GRAPHICS to specify the drive
and path that contains the GRAPHICS command
file.

[printer type] to specify the type of printer you are
using. You can choose from the following type:

COLOR 1 - IBM Personal Computer Color
Printer with black ribbon

COLOR4 - IBM Personal Computer Color
Printer with RGB (red, green, blue, black)
ribbon

COLOR8 - IBM Personal Computer Color
Printer with CMY (cyan, magenta, yellow,
black) ribbon

COMPACT - IBM Personal Computer
Compact Printer

GRAPHICS - IBM Personal Graphics Printer

If you do not specify a printer type, the default is the
GRAPHICS printer.

7-115

GRAPHICS (Screen Print)
Command

/R to print black (as seen on the monitor) and white
(as seen on the monitor) on the printer. If you do
not specify /R, the default is to print black as white
and white as black.

/B to print the background color. This parameter is
only for printer types COLOR4 and COLOR8. If
you do not specify /B, the default is not to print the
background color.

This command increases the resident size of DOS in
memory.

Press the Shift-PrtSc keys to print the screen
contents on the printer. If the screen is in text mode,
the text is printed in less than 30 seconds. If the
screen is in the graphics mode, (modes 4, 5, 6 only)
each time the PrtSc key is pressed, the following
happens:

• In the 320x200 color graphics mode with printer
types GRAPHICS and COLOR 1, the screen
contents are printed in up to four shades of
gray.

• In the 640x200 color graphics mode, the screen
is printed sideways on the paper. The upper
right corner of the screen is printed on the upper
left corner of the paper.

• Printing may take as long as three minutes.

• To invoke the screen print from an assembly
language program, use the following coding
example:

PUSH BP
INT 5
POP BP

7-116

GRAPHICS (Screen Print)

Command

Example: The following example loads graphics support

needed to print the screen contents on a COLOR8
printer. The background colors are printed and
black prints as black and white as white.

A>graphics color8 /b /r

7-117

JOIN
Command

Purpose: Connects a drive to a directory on another drive to
produce a single directory structure from two
separate directories.

Format: [d:]\path]JOlS

[d:][path]JOYN d: d: \ directory

[d:][path]JOYN d: /D

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] to specify the drive and path that contains
the JOIN command file, if it is not in the current
directory of the default drive.

d: to specify the drive to be connected to a directory
on another drive.

d: \ directory to specify the directory that you will
join a drive under. The directory must be at the root
and only one level deep.

If the directory you specify in the path does not
exist, it is created on the drive you specify. If the
directory does exist, it must be empty. An empty
directory only contains the entries . and .. For
example, if the directory of C:\LEVEL1 is empty,
the following is displayed if you type dir c:\levell

7-118

JOIN
Command

Volume in drive C is EMPTY
Directory for C:\LEVEL1

<DIR> 1-01-84 12:03.00 AM

2 Files (s) 1048956 bytes free

/D to disconnect a join. You must specify the drive
letter of the drive whose join you want to delete.
For example, if you joined drive B to the directory
on drive C: \ JOINB, to disconnect the directories,
type:

A>join b: /d

Notes:

1 . The message Directory not Empty is displayed if
the directory you try to JOIN is not empty.

2. The path you specify cannot be the current
directory. If you try to JOIN to the current
directory, the message Invalid parameter appears.

3. The message Invalid drive specification is

displayed if you refer to a joined drive. For
example, if you join drive A, you cannot refer to
the drive letter A until you remove the JOIN
(/D parameter). This means you cannot JOIN
the default drive because you will then be on an
invalid drive.

4. The directory path you specify cannot be the
root directory (\).

5. Type JOIN with no parameters specified to
display the drives and directories that are
currently joined. The information displayed
indicates the drive that is joined and the path the

7-119

JOIN
Command

drive is joined to. For example, the following
message indicates that drive A is joined to the
directory path C:\LEVEL1 .

A: => C:\LEVEL1

6. The entire tree (starting from the root) of the
specified drive is joined, regardless of the
current directory of that drive.

7. JOIN does not allow network drives for either
parameter. The message Cannot JOIN a
network drive appears if you attempt to do so.

8. Unpredictable results occur if the drive being
JOINed is part of a substitution (SUBST) or
reassignment (ASSIGN).

9. BACKUP, RESTORE, FORMAT, DISKCOPY,
and DISKCOMP should not be used while a
JOIN is in effect.

Example: For the following examples, assume:

• The default drive is drive B

• The current directory of drive C is C : \

Joining a Drive to a Directory Path

Assume the directory structure of drive C looks like
this:

C:\

FILES

REPORTS

7-120

JOIN
Command

You can join drive A to the path C: \DRIVEA by
typing:

B>join a: c:\drivea

The directory structure of drive C now looks like
this:

C:\

FILES

REPORTS

DRIVEA

Note: Notice that the directory DRIVEA was
created on drive C by the JOIN command.

If you type dir c:, the following is displayed:

Volume in drive C is FIXEDC
Directory for C: \

FILES <DIR> 8-21-84 2:10.00 PM

REPORTS <DIR> 9-23-84 5:55.00 PM

DRIVEA <DIR> 9-30-84 12:03.00 AM

3 Files(s) 1048956 bytes free

If you type dir a:, the message Invalid drive
specification is displayed because you cannot refer to
a joined drive. If you enter dir c:\drivea , the
directory of the disk in drive A: is displayed. The
"bytes free" displayed are those of C:.

7-121

JOIN
Command

Displaying the Current Joins

The following example displays the current joins
from the previous example.

B>join

The following is displayed:

A: => C:\DRIVEA

Deleting a Join

The following example deletes the join from the
previous example.

B>join a: /d

Now you can refer to drive A because the join is
removed.

Why Use JOIN?

JOIN can be used to help applications take
advantage of fixed and virtual disks. The following
example shows a way that files on A: can be
accessed through C:

D>join a: c:\datafils.dir
D>cd c:\datafils.dir
D>path=c:\
D>dataprog c:

7-122

KE YBxx (Load Keyboard)

Command

Purpose: Loads a keyboard program that replaces the

keyboard program resident in ROM BIOS to support
non-U. S. English keyboards. The xx in the
command represents one of the five keyboard
programs provided on the DOS diskette. Each
command increases the resident size of DOS in
memory by a different amount.

Note: The keyboard programs provided on
DOS 1.10 diskettes are not compatible with
DOS 3.10 and should not be executed when
running under DOS 3.10.

Format: [d:]\path]KEYBUK

or
[d:]\path]KEYBGR

or
[d:]\path]KEYBFR

or
[d:][path]KEYBIT

or
[d:]\path]KEYBSP

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before KEYBxx to specify the drive and
path that contains the KEYBxx; command file.

7-123

KEYBxx (Load Keyboard)
Command

These commands load a program into memory that
replaces the ROM BIOS keyboard program.

• Only one keyboard program should be loaded
after starting DOS. The program remains
resident in memory until you perform a system
reset or power off the computer. If you load a
second keyboard program, it will gain control of
the keystrokes you type. However, the earlier
program will still be in memory and cannot be
returned to.

• You can change from the KEYBxx: program to
the U.S. keyboard format and back again at any
time by holding down the Ctrl and Alt keys and
pressing Fl to change to U.S. format or
Ctrl-Alt-F2 to return to the selected
memory-resident keyboard program.

Note: If you enter a KEYBxx command on
a computer with multilingual keyboard
support in the ROM BIOS, the program
simply sets the current ROM keyboard to
whichever one is appropriate and then exits
leaving nothing resident. Therefore, you
cannot press Ctrl-Alt-Fl to return to a
U.S. keyboard on a machine with ROM
multilingual keyboard support. The reason
for this is that the KEYBxx: program does
not remain resident in memory. Refer to
your Guide to Operations for more
information on how to change the formats
on these types of computers.

• The copy of the DOS diskette you created with
the SELECT command, loads one of these
programs when you start DOS. Refer to
Chapter 4 of the DOS User's Guide for
information on the SELECT command.

7-124

KEYBxx (Load Keyboard)

Command

The table below lists which keyboard program
supports each keyboard. The memory allocated
to each when it is loaded is approximately 2K
bytes.

Command

Keyboard Type

KEYBUK

United Kingdom

KEYBGR

Germany

KEYBFR

France

KEYBIT

Italy

KEYBSP

Spain

Non-U. S. English keyboards have some keys with
characters used by programmers. To use these
characters, press and hold the Ctrl and Alt keys and
press the appropriate character key.

You can get accented characters through the use of
"dead keys," that is, keys that do not produce
characters unless they are used in combination with
another key. To "build" an accented character,
press and release the accent key and then press the
appropriate letter key. To use the accent character
by itself, press the accent key and then press the
space bar.

7-125

KEYBxx (Load Keyboard)
Command

Note: If the dead-key /letter-key combination is
not allowed (not in the following table), you see
the accent followed by the character key you
pressed, and a beep sounds. If you press the
diaeresis, an invalid second key produces a box.

Allowable Dead Key Combinations

Germany

ae'Eidiiaeiou

France

aAeioOiiUyaeiou

Spain

a AeioOiiUyae'Eioil

aei ou aeiou

dead key not supported

Italy

dead key not supported

7-126

LABEL (Volume Label)
Command

Purpose: Allows you to create, change or delete a volume label
on a disk.

Format: [d:][path]LABEL [d:][volume label]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before LABEL to specify the drive and
path that contains the LABEL command file.

[d:] to specify the drive letter of the disk you want to
label. If you do not specify a drive letter, the default
drive is assumed.

[volume label] to specify the volume label. Volume
labels are used to identify a disk. They can be up to
1 1 characters and are in the same format as volume
labels created by FORMAT/V. If you do not
specify a volume label, you are prompted with the
following messages:

Volume in drive X is xxxxxxxxxxx

Volume label (11 characters, ENTER for none)?

To give the disk a volume label, type the label you
want and press Enter.

To change an existing volume label, type the new
volume label and press Enter. The new label you
typed replaces the existing volume label.

7-127

LABEL (Volume Label)
Command

To delete a volume label, do not specify a volume
label; just press Enter. Then you are prompted:

Delete current volume label (Y/N)?

Type y and press Enter. The volume label on the
disk is deleted.

If you type more than 1 1 characters for the volume
label, only the first 1 1 characters are used.

Example: Creating a Volume Label

The following example creates a volume label called
ADDRESS on the diskette in drive A.

A>label a:address

The following example gives the fixed disk C the
label FIXEDISKC.

A>label c:fixediskc

Changing a Disk's Volume Label

The following example changes the volume label of
the diskette in drive A from ADDRESS to
PROGRAMS.

A>label a:

Then you are prompted:

Volume in drive A is ADDRESS

Volume label (11 characters, ENTER for none)?

7-128

LABEL (Volume Label)
Command

Type:

programs

Then press Enter.

Deleting a Volume Label

The following example deletes the volume label
PROGRAMS from the diskette in drive A.

A>label a:

You are prompted:

Volume in drive A is PROGRAMS

Volume label (11 characters, ENTER for none)?

Press Enter. The following prompt is displayed:

Delete current volume label (Y/N)?

Type y and then press Enter. The volume label for
drive A is deleted.

Note: LABEL should not be used with
SUBSTed drives. The root directory of the
actual drive will be the target of LABEL.
LABEL should not be used with ASSIGNed
drives or to label network drives.

7-129

MKDIR (Make Directory)
Command

Purpose: Creates a subdirectory on the specified disk.
Format : MKDIR [d:]path
or
MD [d:]path
Type: Internal External

Remarks: Specify the parameters:

[d:] to specify the drive letter of the disk you want to
create the subdirectory on. If you do not specify a
drive, the default drive is assumed.

[path] to specify the path of directory names.
Subdirectory names are in the same format as
filenames. All characters that are valid for a
filename are also valid for a directory name. For
more information on paths, refer to Chapter 5,
"Tree-Structured Directories" in this manual.

Note: You can create as many subdirectories as
you wish, limited only by available disk space.
However, you should ensure that the maximum
length of any single path from the root directory
to the desired level is 63 characters, including
imbedded backslashes.

Each directory can contain file and directory names
that also appear in other directories. In other words,
two or more files or directories can have the same
name, as long as they are defined in separate
directories.

7-130

MKDIR (Make Directory)

Command

Example: The following example creates the subdirectory
called LEVEL 1 under the root directory.

A>md \levell

The following example creates the subdirectory
LEVEL2 under the subdirectory LEVEL 1.

A>md \levell\level2

If the current directory is \ LEVEL 1, the following
example creates the subdirectory LEVEL2 under the
subdirectory LEVEL 1.

A>md level 2

The last example does the same thing as the second.
Note that in the second example, the first \ tells
DOS to begin its directory search with the root
directory. The absence of a leading \ in the last
example causes DOS to begin at the current
directory.

Note: Care should be taken when making
directories while an ASSIGN, JOIN, or a
SUBST is in effect.

7-131

MODE
Command

Purpose: Sets the way that a printer, a Color/Graphics
monitor adapter, or an Asynchronous
Communications Adapter operates.

Format: [d:]\path]MODE LPT#[:][/i][,[w][,P]]

[d:][path]MODE n

[d\]\path\MODE [/i],w[,T]

[d\]\path\MOVE

C OM«[ : ] ba u d[ ,[parityj[ ,[databits][ ,[stopbitsJ[,F]]] ]

Type:

[d:)[path]MODE LPT#[:] = COM«

Internal External

Remarks: A missing or invalid n or m parameter means that the
mode of operation for that parameter is not changed.

Technical Note: When used in Option 1 (P
option), Option 2 (shifting the screen (R)ight or
(L)eft), Option 3 (P option), or Option 4, the
MODE command causes printer and
Asyncronous Communications Adapter
intercept code to be resident in memory. This
increases the resident size of DOS in memory.

7-132

MODE
Command

The resident portion is common for all three
operations that cause it to be loaded. Once
loaded, invoking another option causing
residency does not cause any additional code to
become resident.

Notes:

1 . Before you can use MODE to redirect parallel
printer output to a serial device, you must
initialize the Asynchronous Communications
Adapter by using Option 3 (see below). If that
serial device is a printer, your serial initialization
command should also include the P parameter.

2. MODE LPT#[:][«][,m] disables the redirection
for the printer designated by the #. Redirection
causes a portion of MODE to remain resident.

3. Because LPT#[:] and COM[:] are DOS device
names, you can specify them with or without the
colon (:). For example, you can specify:

A>mode lptl: 132. ,8

A>mode lptl 132,8

A>mode 1ptl=coml

7-133

MODE
Command

The MODE command has four format options:

Option 1 (For the printer)

MODE LPT#[:][«][,[m][,P]]

where:

# is 1, 2, or 3 (the printer number)

n is 80 or 132 (characters per line)

m is 6 or 8 (lines per inch vertical spacing)

P specifies continuous retry on time-out errors

For example:

A>mode 1 ptl : 132 ,8

sets the mode of operation of printer number 1 to
132 characters per line and 8 lines per inch vertical
spacing. The power-on default options for the
printer are 80 characters per line and 6 lines per
inch. If the printer is reset or initialized, the default
values are set (BASIC initializes the printer).

If you specify an invalid n or m value, the values are
ignored and the previous value is unchanged.

The retry loop can be stopped by pressing
Ctrl-Break. To stop time-out errors from being
continuously retried when you have entered P, you
must use MODE Option 1 without specifying P.

7-134

MODE

Command

Option 2 (For switching Display Adapters, and setting
the display mode of the Color/ Graphics Monitor
Adapter)

MODE«

MODE [n],w[,T]

where:

n is 40, 80, BW40, BW80, CO40, CO80, or

MONO

40 sets the display width to 40 characters per

line (for Color/Graphics Monitor Adapter).

80 sets the display width to 80 characters per

line (for Color/Graphics Monitor Adapter).

BW40 switches the active display adapter to the
Color/Graphics Monitor Adapter, and sets
the display mode to Black and White
(disables color) with 40 characters per line.

BW80 switches the active display adapter to the
Color/Graphics Monitor Adapter, and sets
the display mode to Black and White
(disables color) with 80 characters per line.

CO40 switches the active display adapter to the
Color/Graphics Monitor Adapter, enables
color, and sets the display width to 40
characters per line.

7-135

MODE
Command

CO80 switches the active display adapter to the
Color/Graphics Monitor Adapter, enables
color, and sets the display width to 80
characters per line.

MONO switches the active display adapter to the
Monochrome Display Adapter (which
always has display width of 80 characters per
line).

m is R or L (shift display right or left)

T requests a test pattern used to align the

display

For readability, you can shift a display connected to
a color/graphics monitor adapter 1 character (for 40
columns) or 2 characters (for 80 columns) in either
direction. If you specify T in the MODE command,
a prompt asks you if the screen is aligned properly.
If you type Y the command ends. If you type N the
shift is repeated followed by the same prompt. For
example,

A>mode 80,r,t

sets the mode of operation to 80 characters per line
and shifts the display 2 character positions to the
right. The test pattern is displayed to give you the
opportunity to further shift the display without
having to enter the command again.

Note: Shifting the display on an IBM Personal
Computer AT causes all of MODE'S resident
code to be loaded.

7-136

MODE
Command

Option 3 (For Asynchronous Communications
Adapter)

MODE COMn[:]baud[,parity[,databits[,stopbits[,?]\]]

where:

n Either 1 or 2 (Asynchronous

Communications Adapter number)

baud 1 10, 150, 300, 600, 1200, 2400, 4800, or

9600

Note: Only the first 2 characters are
required; subsequent characters are
ignored.

parity Either N (none), O (odd), or E

(even) — (default = E)

databits Either 7 or 8 (default = 7)

stopbits Either 1 or 2 (if baud equals 110, default
= 2; if baud does not equal 110, default
= D

These are the protocol parameters. They are used to
initialize the Asynchronous Communications
Adapter. When you specify the protocol, you must
specify at least the baud rate. The other parameters
can be omitted, with the defaults accepted, by
entering only commas. For example,

A>mode coml:12,n,8,l,p

sets the mode of operation to 1200 baud rate, no
parity, 8 databits, and 1 stopbit. To use the defaults
listed in the definitions above, you enter:

7-137

MODE
Command

A>mode coml:12, , , ,p

The parity defaults to even, the databits defaults to
seven, and the stopbits defaults to one.

The P option indicates that the asynchronous adapter
is being used for a serial interface printer. If you
enter the P, time-out errors are continuously retried.
You can stop the retry loop by pressing Ctrl-Break.
To stop the time-out errors from being continuously
retried when you have entered P, you must
reinitialize the asynchronous adapter without
entering the P. P option causes a portion of MODE
to remain resident.

Option 4 (To redirect parallel printer output to an
Asynchronous Communications Adapter)

MODE LPT#[:]=COM«

where:

# Either 1, 2, or 3 (printer number)

n Either 1 or 2 (Asynchronous

Communications Adapter number)

All output directed to printer LPT# is redirected to
the asynchronous adapter n.

7-138

MORE Filter
Command

Purpose: Reads data from the standard input device, and sends
one screen of data to the standard output device, and
then pauses with the message — More — .

Format: [d:]\path]MORE

Type: Internal External

Remarks: Specify the parameters:

Example:

[d:][path] before MORE to specify the drive specifier
and path that contains the MORE command file.

Pressing any character key causes another screen of
data to be sent to the standard output device. This
process continues until all input data is read.

The following example displays the contents of the
file TEST. ASM one screen at a time. When the
screen is full, the message — More — appears on the
bottom line. You can press any key to see the next
screen.

A>more <test.asm

The following example pipes the output of the
TREE command to the MORE filter. This is useful
because when a full screen of output from TREE is
displayed, the output pauses and the message
—More— is displayed. When you want to continue
with the display, press any key.

A>tree J more

7-139

PATH (Set Search Directory)
Command

Purpose: Searches specified directories for commands or batch
files that were not found by a search of the current
directory.

Format: PATH [[d:]path[[\[d:]path]...]]

PATH;

Type: Internal External

***

Remarks: You may specify a list of drives and path names,

separated by semicolons (note that path names must
be specified and will not default to the current
directory). Then, when you enter a command that is
not found in the current directory of the drive that
was specified (or implied) with the command, DOS
searches the named directories in the sequence you
entered them. The current directory is not changed.

Typing PATH with no parameters displays the
current path. Typing PATH with only a semicolon
(PATH ;) resets the search path to null (no extended
search path). This is the default when DOS is
started. In this case, DOS searches only the current
directory for commands and batch files.

7-140

PATH (Set Search Directory)

Command

Notes:

1. Erroneous information in the paths, such as
invalid drive specifications or imbedded
delimiters, will not be detected until DOS
actually needs to search the specified paths.

2. If a path is specified that no longer exists at the
time DOS uses it to search for a command or
batch file, DOS ignores that path and goes on to
the next.

3. PATH only finds files that can be executed;
such as .COM, .EXE, and .BAT files. PATH
will not find files with any other extensions.

4. A copy of the environment is saved with
terminate and stay-resident programs. Invoking
programs with a resident portion (MODE,
PRINT, GRAPHICS) before a large path is set
saves usable memory.

5. Terminate and stay-resident programs are
loaded above the environment area so growth of
the environment is limited to 128 bytes or the
current size, whichever is greater.

Example: For the following examples, assume the program
MYPROG.COM is only in directory MYDIR on
drive B, and that the default drive is drive A.

The following example instructs DOS to look in the
current directory of the specified drive, followed by
A:\LEVEL2\LEVEL3, then B:\MYDIR for a
command you specify.

A>path a: \leve!2\leve13;b: \mydir

7-141

PATH (Set Search Directory)
Command

If the command typed is not found in any of the
directories specified in PATH, the following message
is displayed:

Bad command or filename

In the previous example, if you type the command:

A>myprog

DOS searches the three specified directories, finding
the program MYPROG in B: \MYDIR.

To display the current path, type:

A>path

The result is:

PATH=A:\LEVEL2\LEVEL3;B:\MYDIR

The following example causes DOS to search the
current directory of C:, then D:\tools.

A>path c: . ; d:\tools

7-142

Command

Purpose: Prints a queue (list) of data files on the printer while
you are doing other tasks on the computer.

Format: [d:][path]PMKT[/D:device][/B:buffsiz][/\J:busytick]
[ / M : maxtick] [ / S : times lice] [ /Q : quesiz]
[/C][/T][/F][[d:][path][filename]lext]...]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before PRINT to specify the drive and
path that contains the PRINT command file.

/D'.device to specify the print device. If not
specified, the default device PRN is assumed.

Important: If you specify /D, it must be the first
parameter.

/B:buffsiz to set the size in bytes of the internal
buffer. The default value is 512 bytes. Increasing
the value of B may enhance the performance of the
PRINT command.

/Q.quesiz to specify how many print files you can
have in the queue. The range of values is from 1 to
32 files. The default value is 10.

/Suimeslice to specify the time-slice value. The
default is 8 time slices. The range of values is 1 to

255.

/\J:busytick to specify the number of clock ticks that
PRINT will wait for until the print device is

7-143

Command

available. /U is called busyticks. The default value
for busytick is 1 . If PRINT waits longer than U
busyticks, it gives up its time slice.

/M:maxtick to specify how many clock ticks PRINT
can have to print characters on the print device. /M
is called maxticks. The default value for maxtick is 2
maxticks. The range of values is from 1 to 255
maxticks. This parameter does not need to be
specified each time you use PRINT. Specify it only
the first time.

/T to set the terminate mode. All queued files are
canceled from the print queue. If a file is currently
being printed, the printing stops, a cancelation
message is printed, the paper is advanced to the next
page, and the printer's alarm sounds.

/C to set the cancel mode. Allows you to select
which file or files to cancel. The preceding filename
and all following filenames entered on the command
line are canceled from the print queue until a /P is
found on the command line, or until you press the
Enter key.

/P to set the print mode. The preceding filename
and all following filenames are added to the print
queue until a /C is found on the command line, or
until you press the Enter.

The parameters /D, /B, /Q, /S, /U, and /M can
only be specified the first time you use PRINT. If
you specify them again, the following message is
displayed:

Invalid Parameters

You can enter more than one filename on the
command line, each with appropriate parameters.

7-144

Command

Global filename characters * and ? are allowed in the
filename. Once a file has been queued, you can
change the current directory without affecting the
printing of the files already in the print queue.

The first time this command is issued, it increases the
resident size of DOS in memory.

If no parameters are specified and you press Enter,
the files listed on the command line are queued for
printing (/P is assumed).

If PRINT is typed with no parameters, PRINT
displays the names of the files currently in the print
queue.

If you did not specify the device name using /D the
first time the PRINT command is executed after you
start your system, the following message is displayed
on the display screen:

Name of list device [PRN]:

This allows you to specify the output list device,
LPT1, LPT2, LPT3, PRN, COM1, COM2, AUX,
etc. The default is PRN, and will be selected if you
press Enter.

Note: Be sure the device you name is physically
attached to your system; naming a nonexistent
device will cause unpredictable system behavior.

The files are queued for printing in the order entered.
After each file is printed, the printer paper is
advanced to the next page. Any tab characters
found are expanded with blanks to the next
8-column boundary.

7-145

Command

If PRINT encounters a disk error while attempting to
read the file to be printed, PRINT will cause:

• The file currently printing to be canceled

• The disk error message to be printed on the
printer

• The printer paper to be advanced to the next
page and the alarm to be sounded

• The remaining files in the print queue to be
printed

If the /T or /C parameters are used to cancel a file
or files currently being printed:

• The printer alarm sounds.

• A file cancelation message prints on the printer.
If /T, the following message prints:

All files canceled by operator.

If /C, the name of the canceled file is printed
followed by this message:

File canceled by operator

• The printer paper advances to the next page.

• If all files in the print queue have not been
canceled, printing resumes with the first file
remaining in the print queue.

7-146

PRINT
Command

Notes:

1 . The disk containing the files being printed must
remain in the specified drive until all printing is
complete. Any file in the print queue must not
be altered or erased until after it has been
printed.

2. The printer cannot be used for any other
purpose while PRINT has data to print. Any
attempt to use the printer (Shift-PrtSc, LLIST,
Ctrl-PrtSc, LPRINT, etc.) results in an
"out-of-paper" indication until all files have
been printed or printing is terminated (/T).

3. You cannot use PRINT on a network server
computer.

Example: In this example, the PRINT command is being used
for the first time since the system was started. The
command:

A>print a: tempi . tst

has just been entered, DOS responds with:

Name of list device [PRN]:

Press the Enter key to send output to the printer.

Then it adds the file TEMPI. TST from drive A to
the print queue and sends the output to the device
"PRN" printer. The command:

A>print /t

empties the print queue. Any other information on
the line is ignored.

7-147

PRINT
Command

The command:

A>print temp.*/c

removes all TEMP.??? files from the print queue
that have the same drive letter as the default drive.
The command:

A>print a: tempi . tst/c a: temp2 . tst a:temp3.tst

removes the three files TEMPI, TEMP2, and
TEMP3 on drive A from the print queue. The
command:

A>print tempi. tst/c temp2.tst/p tempS.tst

removes file TEMPI. TST from the print queue,
adds the files TEMP2.TST and TEMP3.TST to the
print queue. The command:

A>print tempi. tst temp2.tst temp3. tst/c

adds files TEMPI. TST and TEMP2.TST to the
print queue, then removes TEMP3.TST from the
print queue.

7-148

PROMPT (Set System Prompt)

Command

Purpose: Sets a new DOS prompt.
Format: PROMPT [prompt-text]
Type: Internal External

Remarks: Specify the parameter:

prompt-text to specify the text for the new system
prompt. The prompt-text can contain special
meta-strings that are in the form $c. The following
are meta-strings that can be included in the
prompt-text:

Where c is one of the following:

$ The $ character.

t The time.

d The date.

p The current directory of the default drive.

v The version number.

n The default drive letter.

g The > character.

1 The < character.

b The | character.

q The = character.

h A backspace; the previous character is erased.

e The ESCape character.

The CR LF sequence (go to beginning of new

line on the display screen).

Any other value for c is treated as a null character
and is ignored by PROMPT.

7-149

PROMPT (Set System Prompt)
Command

Type PROMPT with no parameters to reset the
prompt to the normal DOS prompt.

Example: The following example sets the DOS prompt to the
default drive letter plus the character >.

A>prompt $n$g

The following example sets the DOS prompt to the
message HELLO.

A>prompt hello

The following example sets the DOS prompt to the
current directory of the default drive plus the >
character.

A>prompt $p$g

Note: Include this statement in an
AUTOEXEC.BAT file so that every time you
start DOS, the DOS prompt tells you what
directory you are in (the current directory).

If the current directory of drive A is \ LEVEL 1, the
DOS prompt would display:

A:\levell>

The following example sets the DOS prompt to
display the date and time as follows:

Time = (current time)

Date = (current date)

A>prompt time = $t$_date = $d

7-150

PROMPT (Set System Prompt)

Command

If you want to create a prompt that begins with any
of the DOS command delimiters (such as semicolon
or blank), you can precede that character with a null
meta-string. In this case, the character is treated as
the first character of the prompt, rather than as a
delimiter between the word PROMPT and its
parameter. For example:

A>prompt $a;abc

causes the PROMPT command to interpret the $A
as a null character, because A is not one of the
defined characters in the above list. All characters
following the null character become the new system
prompt.

You can use the PROMPT command to issue escape
sequences to ANSI. SYS. If you started your system
with the command, DEVICE =ANSI.SYS in your
CONFIG.SYS file, the following example displays
the current directory on the top row of the screen,
and a minus - on the current line.

A>prompt $e[s$e[24A$p$e[u-

The A in the escape sequence must be uppercase.
See Chapter 3, "Using Extended Screen and
Keyboard Control" in the DOS Technical Reference,
Version 3.10.

Notes:

1 . A copy of the environment is saved with

terminate and stay-resident programs. Invoking
programs with a resident portion (MODE,
PRINT, GRAPHICS) before a large path is set
saves usable memory.

7-151

PROMPT (Set System Prompt)
Command

2. Terminate and stay-resident programs are

loaded above the environment area so growth of
the environment is limited to 128 bytes or the
current size, whichever is greater.

7-152

RECOVER
Command

Purpose:

Recovers files from a disk that has a defective sector.
You can recover the file that contains the bad sector
(minus the data in the bad sector). Or, all the files
on the disk can be recovered if the directory has
been damaged.

Format: [d:]\path]RECOVER [d:][path]filenamelext]

Type:

[d:][path]RECOVER d:
Internal External

Remarks: Specify the parameters:

[d:][path] before RECOVER to specify the drive and
path that contains the RECOVER command file.

[d:][path]filename[.ext] to specify the name of the file
you want to recover.

Use the first RECOVER format to recover the
specified file. If you do not specify a drive, the
default drive is used. If you do not specify a path,
the current directory is used. The size of the
recovered file is a multiple of the DOS allocation unit
size. In most cases, this is larger than the original file
size. The data in the bad sector is not recovered.

Use the second RECOVER format to recover all
files.

If the sum of the number of files in the root and the
number of files in subdirectories is greater than the

7-153

RECOVER
Command

possible number of entries in the root (1 12 for
double-sided diskettes), you have to do multiple
recovers to save the entire disk. Issue RECOVER
using the second format to recover as many entries
as will fit in the root directory. Examine the
recovered files and copy the ones you want to save
to another disk. Delete some or all of the files you
have already recovered from the damaged disk from
which you are recovering. Issue RECOVER again to
recover more files. Continue this procedure until all
files are recovered.

This form of the RECOVER command should only
be used if the directory of the disk has become
unusable. Because RECOVER has no way to know
whether the data in the directory is valid or not, it
must assume that the entire directory is invalid, and
therefore recovers all files into filenames of the form
shown below, including any files for which there may
still have been valid directory entries.

Text files will normally require re-editing to remove
unwanted data from the end of the recovered file
before they can be used for normal processing.

Note: You cannot use the RECOVER
command on a network disk.

Example: The following example recovers the file MYPROG
from the disk in drive A.

A>recover a:myprog

The disk file MYPROG on drive A is read
sector-by-sector, skipping the bad sectors.

The following example recovers the contents of an
entire disk from drive A.

7-154

RECOVER
Command

A>recover a:

The disk file allocation table on drive A is scanned
for chains of allocation units. A directory is created
for each chain of allocation units in the form:

FILEnnnn.REC

Where nnnn is a sequential number starting with
0001. Each FILErtwzw.REC points to one of the
recovered files on the disk.

7-155

RENAME (or REN)
Command

Purpose: Changes the name of the file specified in the first
parameter to the name and extension given in the
second parameter.

Format: REN[AME] [d:][path]filename[.ext] filename[.ext]

Type: Internal External

* * *

Remarks: You can use the abbreviated form REN for the

RENAME command. You can also use the global
characters ? and * in the parameters. For more
information about global characters, refer to "Global
Filename Characters" in Chapter 2. A path can be
specified only with the first filename; the file will
remain in the same directory after its name has been
changed.

Example: The following example renames the file ABODE on
drive B to HOME.

A>rename b: abode home

The following example renames the file ABODE on
drive B to ABODE.XY.

A>ren b:abode *.xy

The following example renames the file
MYPROG.COM in the directory \LEVEL1 on
drive B to YOURPROG.COM.

A>ren b:\levell\myprog.com yourprog.com

7-156

RESTORE
Command

Purpose: Restores one or more backup files from a disk to
another disk.

Format: [d:][path]RESTORE d:

[d:][path]filename[.ext][/S][/V]

Type: Internal External

Remarks: Specify the parameters:

[d:]\path] before RESTORE to specify the drive and
path that contains the RESTORE command file.

d: to specify the drive that contains the BACKUP
files (source).

[d:][path]filename[.ext] to specify where you want to
restore the files and what files from the source you
want to restore.

/S to restore all files in subdirectories in addition to
the files in the specified directory. This includes
subdirectories at all levels beyond the specified
directory.

/P to have RESTORE prompt you before restoring
files that have changed since they were last backed
up, or that are marked read-only. You can then
choose to restore the file or not. Read-only is a file
attribute that you can set by using the ATTRIB
command. The two DOS system files
(IBMBIO.COM and IBMDOS.COM) are marked
read-only when they are created by the FORMAT
and SYS commands.

7-157

RESTORE
Command

The files being restored must have been placed on
the source by the BACKUP command.

Files are restored to the current directory if you do
not specify a path. If you specify a path, you must
also specify a filename.

Global filename characters are allowed in the
filename, and cause all of the files matching the
filename to be restored.

When RESTORE prompts you to insert the source,
make sure you insert the first diskette that might
contain the file you want to restore. If you are not
sure, insert source number 1. If the file is not on the
diskette you inserted, RESTORE prompts you to
insert the next target.

If you are sharing files, you can only restore files that
you have access to. If you attempt to access a file
that you do not have access to, the following
message is displayed:

PATHNAME\ FILENAME

Not able to restore at this time

If you use global filename characters, RESTORE
prompts you to insert the next diskette after it has
restored all files on the backup diskette that match
the specified filename.

If you are restoring files that were backed up using a
previous version of DOS, it is recommended that you
use the RESTORE /P parameter. This will prompt
you before restoring the DOS system files
IBMBIO.COM and IBMDOS.COM. You should
respond with a N to the prompt asking you if you
want to restore the file. This will avoid overlaying
the DOS 3.10 version of these files with versions

7-158

RESTORE
Command

from previous levels of DOS. We recommend that
you use the SYS command or FORMAT /S and then
copy the current version on COMMAND.COM to
the root directory before restoring if you want the
disk to be bootable.

The RESTORE command sets the ERRORLEVEL
(see Batch Commands) as follows:

Normal completion

1 No files were found to restore

2 Some files not restored due to sharing conflicts

3 Terminated by user (Ctrl-Break or ESC)

4 Terminated due to error

These codes can be used with the batch processing
IF subcommand to control subsequent error level
processing.

Example: The following example restores all files (including
subdirectories /S) on the backup diskettes to fixed
disk drive C:

A>restore a: c: \*.* /s

The following example restores files from the
backup disk in drive A that have a filename
extension of .DAT to drive C.

A>restore a: c:*.dat

7-159

RESTORE
Command

The following example restores three different files
from the backup diskettes to the default fixed disk
drive:

Orestore a: \levell\filel.dat
Orestore a: \levell\level2\file2.dat
Orestore a: \levell\level3\file3.dat

The following example restores all files from the
backup disk drive C, and prompts you if any files on
drive C have changed since the last backup or if any
files are marked read-only (/P).

A>restore c:/p

Important: Do not RESTORE if a JOIN, ASSIGN,
or SUBST was in effect during the BACKUP.

7-160

RMDIR (Remove Directory)

Command

Purpose: Removes a subdirectory from the specified disk.
Format: RMDIR [d:]path
or
RD [d:]path

Type: Internal External

***

Remarks: The directory must be empty before it can be
removed with the exception of the "." and ".."
entries. You cannot remove subdirectories that
contain hidden files. The last directory name in the
path is the directory to be removed.

Note: The root directory and the current
directory cannot be removed.

Example: The following example removes the entry for
LEVEL2 from the directory LEVEL1.

A>rd b:\levell\level2

Note: Exercise care in using RMDIR while a
JOIN or an ASSIGN is in effect. You cannot
remove a directory if it has been substituted
(SUBST).

7-161

SELECT
Command

Purpose: Allows you to select the keyboard layout and the
date and time format.

Format: [d:][path]SELECT xxxyy

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before SELECT to specify the drive and
path that contains the SELECT command file.

xxx to specify the country code. The country code
tells DOS the date and time format. It also tells DOS
the currency symbol and the decimal separator.
Choose the value for xxx from the table below.

yy to specify the keyboard code. The keyboard code
tells DOS which keyboard layout you want to use.
Choose the values for xxx and yy from the table
below.

Country

Country
Code

Keyboard Code

United States

001

France

033

Spain

034

7-162

SELECT
Command

Country

Country
Code

Keyboard Code

Italy

039

United Kingdom

044

Germany

049

The SELECT command uses DISKCOPY to make a
copy of your DOS diskette. It also creates the
following two files on the copy of the DOS diskette:

A CONFIG.SYS file that contains the
COUNTRY = command

An AUTOEXEC.BAT file that contains the
KEYbxx command (except in the case of a U.S.
keyboard)

Refer to Chapter 4 "Starting DOS" in the DOS
User's Guide for more information.

7-163

SET (Set Environment)
Command

Purpose: This command inserts strings into the command

processor's environment. A copy of the entire series
of strings in the environment is made available to all
commands and applications.

Format: SET [name=[parameter\]

Type: Internal External

***

Remarks: The entire string (beginning with name) is inserted
into a block of memory reserved for environment
strings. Any lowercase letters in the name are
converted to uppercase letters when added to the
environment (including foreign language characters);
the remainder of the line is inserted as you typed it.
If the name already exists in the environment, it is
replaced with the new parameter.

If the SET command is typed with no name specified,
then the current set of environment strings is
displayed.

If a name is specified, but the parameter is not
specified, then the current occurrence of
name=parameter is removed from the environment.

A copy of the environment (series of names and
parameters) is made available to all DOS commands
and applications (see "Program Segment Prefix" in
Chapter 7 of the DOS Technical Reference).

7-164

SET (Set Environment)
Command

Notes:

1 . DOS automatically adds any PROMPT or
PATH commands to the environment when you
enter them. You do not need to use the SET
command to add either of these two commands
to the environment.

2. One of the strings in the environment (placed
there by DOS when it starts up) will always be a
COMSPEC = parameter. That parameter
describes the path that DOS uses to reload the
command processor when necessary.

3. If you have not loaded a program that remains
resident (such as MODE, PRINT, or
GRAPHICS), DOS expands the environment
string area to hold additional strings. If you have
loaded a program that remains resident, DOS is
unable to expand the environment area beyond
127 bytes. If the environment area has already
expanded beyond 127 bytes when you load a
program that is to remain resident, DOS is
unable to expand the environment area beyond
that point. The message Out of environment
space appears if you issue a SET command that
would cause the combined environment strings
to exceed 127 bytes.

4. A copy of the environment is saved with
terminate and stay-resident programs. Invoking
programs with a resident portion (MODE,
PRINT, GRAPHICS) before a large
environment is set saves usable memory.

7-165

SET (Set Environment)
Command

Example: This example adds the string PGMS= \ LEVEL 1 to
the environment. When an application program
receives control, it could search the environment for
the name PGMS, and use the supplied parameter as
the directory name to use for its files:

A>set pgms=\levell

The following example removes PGMS= \ LEVEL 1
from the environment:

A>set pgms=

You can select the strings in the environment. For
example, typing:

A>set abc=xyz

adds the string ABC=xyz to the other strings
already in the environment (note the conversion of
abc to uppercase ABC). In this way, it is possible
for you to type keywords and parameters that are not
meaningful to DOS, but can be found and
interpreted by applications designed to examine the
environment.

7-166

Command

Purpose: Loads support for file sharing.

Note: Refer to Int 21H function calls 3DH and
5CH in Chapter 6 of the DOS Technical
Reference for more information on file sharing
and locking.

Format: [d:][path]SHARE [/F:filspace][/L: locks]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before SHARE to specify the drive and
path that contains the SHARE command file.

/F:filespace to allocate file space in bytes for the
area used for recording the information necessary for
file sharing. Each open file requires the length of the
full filename plus 1 1 bytes. The default value is
2048 bytes.

/L'Jocks to allocate space for the number of locks
you want. The default value is 20 locks.

7-167

Command

If you load SHARE, all read or write requests are
validated against the file sharing code. If filesharing
is installed and you try to re-install it, the following
message is displayed:

Share Already Installed

Example: The following example loads file sharing support.

A>share

Note: If you load SHARE, the table for FCB
control is checked. If you specified FCBS=4,0
(the default) in CONFIG.SYS, the table is
adjusted to 16,8.

7-168

SORT Filter
Command

Purpose: Reads data from the standard input device, sorts the
data, then writes the data to the standard output
device.

Format: [d:][path]SORT [/R] [/+ n]

Type: Internal External

***

Remarks: Specify the parameters:

[d:][path] before SORT to specify the drive and path
that contains the SORT command file.

/R to sort in reverse order. For example, Z comes
before A.

/ +n to start sorting with column n. The n is an
integer value. If you do not specify n the default is
column 1 . The maximum file that you can sort is
63K.

The output filename must be different than the input
filename.

Notes:

Characters are sorted according to their binary value
with the following exceptions:

1 . Lowercase letters a-z are equated to uppercase
A-Z.

2. Some characters above 127 are collated
according to the following chart:

7-169

SORT Filter
Command

ASCII

value
(decimal)

ASCII weight

ASCII

value

(decimal)

ASCII weight

128

150

129

151

130

152

131

153

132

154

133

155

134

156

135

157

136

158

137

159

138

160

139

161

140

162

141

163

142

164

143

165

144

166

145

167

146

168

147

169

148

170

149

171

7-170

SORT Filter
Command

ASCII

value

(decimal)

ASCII weight

ASCII

value
(decimal)

ASCII weight

172

175

173

225

174

Example: The following example reads the file UNSORT.TXT,
sorts it in reverse order, and then writes the output to
the file SORT.TXT.

A>sort /r <unsort.txt >sort.txt

The following example pipes the output of the DIR
command to the SORT filter. Then the directory
listing is sorted starting with column 14 (column 14
of a directory listing contains the file size). The
output is sent to the standard input device.

A>dir ! sort /+14

7-171

SUBST(Substitute)
Command

Purpose: Allows you to use a different drive specifier to refer
to another drive or path.

Note: If you use applications that do not
recognize paths, SUBST allows you to specify a
drive letter for a path.

Format: [d: ][path] SUBST d: d.path

[d:]\path\$UBST d\ /D

[d:]\path] SUBST
Type: Internal External

Remarks: Specify the parameters:

[d:][path] to specify the drive and path that contains
the SUBST command file.

d: to specify the drive letter that you want to use to
refer to another drive or path.

d:path to specify the drive or path that you want to
refer to with a nickname. The path you specify
should start from the root directory.

/D to delete a substitution. You must specify the
drive letter of the drive whose substitution you want

7-172

SUBST(Substitute)
Command

to delete. For example, if you substituted the drive
G for the path C: \ LEVEL 1, to remove the
substitution, type:

A>subst g: /d
Notes:

1 . The first drive letter you specify depends on the
value of the LASTDRIVE configuration
command. If you do not specify the
LASTDRIVE command in your CONFIG.SYS
file, the default value is LASTDRIVE=E. This
means that you can substitute the drive letters A
through E. To specify a drive letter greater than
E, set LASTDRIVE equal to a letter A - Z. For
example, to SUBST the drive letter G, the
LASTDRIVE command must be greater than or
equal to G. Refer to Chapter 4 "Configuring
Your System" for more information on the
LASTDRIVE command.

You can think of this drive letter as a
"nickname" for a drive or path that you can
access. For example, if you substitute the drive
letter G for the path C: \ LEVEL 1 \LEVEL2 to
refer to C:\LEVEL1\LEVEL2\FILE1 you
can type:

A>dir g:filel

Instead of typing:

A>dir c:\levell\level2\filel

2. The drive specifiers for both drives you specify
must be different.

7-173

SUBST(Substitute)
Command

3. The first drive letter that you specify cannot be
the same as the default drive.

4. If you specify a path, it is assumed that the path
starts from the root directory.

5. Neither parameter can refer to a network drive.
If you do refer to a network drive, the message
"Cannot SUBST a network drive" appears.

6. The following commands should be used with
care while a substitution is in effect: CHDIR,
MKDIR, RMDIR, and PATH.

7. The following commands should not be used
while a substitution is in effect: ASSIGN,
BACKUP, DISKCOMP, DISKCOPY, FDISK,
FORMAT, JOIN, LABEL, and RESTORE.

8. Type SUBST with no parameters to display the
current substitutions. The output is displayed in
this form:

G: => D:\PATH

9. The message Invalid Parameter is displayed if:

You type an incorrect drive specifier

You try to substitute the default drive

You specify /D without specifying the drive
letter

10. The message Invalid Path is displayed if you
specify a path that doesn't exist.

7-174

SUBST(Substitute)
Command

Example: For the following examples, assume:

• The default drive is drive B

• The current directory of drive C: is
C:\REPORTS\FILES

. LASTDRIVE=H

C:\

REPORTS

GAMES

FILES

Creating a Substitution

The following example substitutes drive G for the
path C:\REPORTS\FILES

b>subst g: c:\reports\files

If you want to list the directory of
C:\REPORTS\FILES, you can type:

B>dir g:

Remember, the drive specifiers must be less than or
equal to the value specified for LASTDRIVE in your
CONFIG.SYS file. For example, in order for drive
G to be valid, the LASTDRIVE command must be
greater than or equal to g (LASTDRIVE = g).

7-175

SUBST(Substitute)
Command

Displaying the Current Substitutions

The following example displays the current
substitutions:

b>subst

The following is displayed:

G: => C:\REPORTS\FILES

The message indicates that drive G: is substituted
for the path C: \ REPORTS \ FILES. Now when you
refer to drive G, the directory
C:\REPORTS\FILES is used.

7-176

SUBST(Substitute)
Command

Deleting a Substitution

The following example removes the substitution as it
appeared in the previous example:

subst g: /d

Why Use SUBST?

Substituting a drive letter for a path can be useful if
you use applications that do not recognize paths.
For example, if you want to edit the file RECIPES in
the directory C:\FOOD\FILES, you can substitute
the drive letter F for this directory path. Then when
you want to edit RECIPES use the drive letter F
instead of the path C: \ FOOD \ FILES. You can
then refer to the file as F:RECIPES. Remember,
you must have LASTDRIVE=F to do this
substitution.

7-177

SYS (System)
Command

Purpose:

Format:
Type:

Transfers the operating system files IBMDOS.COM
and IBMBIO.COM from the first drive specified to
the second drive specified.

Note: SYS does not transfer the file
COMMAND.COM. You must copy this file
into the root directory of the disk.

[d:][path]SYS d:

Internal External

***

Remarks: Specify the parameters:

[d:][path] before SYS to specify the drive and path
that contains the SYS command file.

d: to specify the disk drive that you want to transfer
the operating system files to.

The directory of the disk in the specified drive must
be completely empty, or the disk must have been
formatted by a FORMAT d:/S or FORMAT d:/B
command to contain directory entries for the DOS
files IBMBIO.COM and IBMDOS.COM. This is
necessary because DOS startup requires these files to
occupy the first two directory entries, and because
IBMBIO.COM must reside on consecutive sectors
on the disk.

7-178

SYS (System)
Command

Notes:

1 . SYS lets you transfer a copy of the operating
system files to an application program diskette
designed to use DOS, but sold without it. In this
case, the space required for the DOS files has
already been allocated, although the DOS files
are not actually present. The SYS command
transfers the files to the allocated space.

2. You cannot use the SYS command on a network
drive.

7-179

TIME
Command

Purpose: Permits you to enter or change the time known to the
system. Whenever you create or add to a file, the
time is recorded in the directory. You can change
the time from the console or from a batch file.

Format: TIME [hh:mm\[:ss[.xx]]\

Type: Internal External

***

Remarks: Specify the parameters:

to specify the hours. Type one or two numbers

hh .. _ r ..__,

from to 23 for the hours

mm to specify the minutes. Type one or two
numbers from to 59 for the minutes.

ss to specify the seconds. Type one or two numbers
from to 59 for the seconds.

xx to specify the hundredths of seconds. Type one
or two numbers from to 99 for the hundredths of
seconds.

Notes: If you type TIME with no parameters, the
following prompt is displayed:

Current time is hh:mm:ss.xx
Enter new time:_

To leave the time as-is, press Enter. To change the
time, type the new time and then press Enter.

1 . Separate the hours, minutes, and seconds using a
colon (:) or period (.). Separate the hundredths

7-180

TIME

Command

of seconds using a period (.) or a comma (,),
depending on the decimal separator that is
displayed on the screen.

2. If you type a valid time, the new time is
accepted and the DOS prompt is displayed. If
the time is invalid, the following prompt is
displayed:

Invalid time
Enter new time_

3. If you enter any information (for example, just
the hours and minutes, and press Enter), the
remaining fields are set to zero.

4. Any time is acceptable as long as the digits are
within the defined ranges.

5. You can change the format of the time by using
the COUNTRY configuration command. Refer
to Chapter 4 "Configuring Your System" for
information on the COUNTRY command.

6. If you are using an IBM Personal Computer AT,
changing the time does not change the system
clock. Refer to your GTO for information on
the system clock.

Example: The following example sets the time to 13:55:00.00.

A>time

Current time is 00:25:16.65

Enter new time: 13:55

7-181

TREE
Command

Purpose: Displays all of the directory paths found on the
specified drive, and optionally lists the files in the
root directory and each subdirectory.

Format: [d:][path]TREE [d:][/F]

Type: Internal External

* * *

Remarks: Specify the parameters:

Example:

[d:][path] before TREE to specify the drive and path
that contains the TREE command file.

[d:] to specify the drive whose directory paths you
want to display. If not specified, the default drive is
used.

/F to also display the names of files in the root
directory and in all subdirectories.

For each directory found, its full path name is
displayed, along with the names of any directories
defined within it (these are called subdirectories in
the output). To pause the screen output, use the
Pause Screen function or pipe the output to the
MORE filter.

The following example lists all the directory paths
and the names of all files in the root directory and
each subdirectory on drive B. The output is placed
in the file TREE.LST in the current directory of
drive A.

A>tree b:/f >tree.lst

7-182

TREE
Command

Following is an example of a directory path listing.
If the disk called MYDISK in drive A had the
following directory structure:

ROOTDIR

SOURCE

LEVEL2

MYPRO
MYPRO

G1.ASM
G2.ASM

Nof

LEVEL3

MYPROG1.EXE

7-183

TREE
Command

Then TREE /F would display:

DIRECTORY PATH LISTING FOR VOLUME MYDISK

Files: None

Path: \ SOURCE

Subdirectories: None

Files: MYPROG1 ASM

MYPROG2 .ASM

Path: \LEVEL2
Subdirectories: LEVELS
Files: None

Path: \LEVEL2\LEVEL3

Subdirectories: None

Files: MYPROG1 .EXE

The following example lists all the directory paths
and filenames of the root directory and of all
subdirectories on drive A. The output is sent to the
printer.

A>tree a:/f >prn

7-184

TYPE

Command

Purpose: Displays the contents of the specified file on the
standard output device.

Format: TYPE [d:][path]filename[.ext]

Type: Internal External

Remarks: The data is unformatted except that tab characters
are expanded to an 8-character boundary; that is,
columns 8, 16, 24, etc.

Notes:

1 . Use the Print Screen function to print the
contents of a file as it is displayed. You can also
redirect the output to a file or the printer.

2. Text files appear in a legible format; however,
other files, such as object program files, may
appear unreadable due to the presence of
nonalphabetic or nonnumeric characters.

3. Global filename characters are not allowed in
the filename or extension.

Example: The following example displays the file

MYFILE.ONE on drive B on the standard output
device.

A>type b:myf i 1 e.one

7-185

VER (Version)
Command

Purpose: Displays the DOS version number that you are

working with on the display screen or the standard
output device.

Format: VER

Type: Internal External

***

Remarks: The DOS version consists of a single-digit major

version number, followed by a period, followed by a
two-digit minor version number.

Example: The following example displays the current DOS
version number.

A>ver

The result is:

IBM Personal Computer DOS Version 3.10.

The major version number is 3 and the minor
version number is 10.

7-186

VERIFY
Command

Purpose: Verifies that the data written on a disk has been
correctly recorded.

Format: VERIFY [ON | OFF]

Type: Internal External

***

Remarks: VERIFY ON remains on until it is turned off

through the SET VERIFY System Call or a VERIFY
OFF command. When ON, DOS performs a verify
operation following each disk write operation, to
verify that the data just written can be read without
error. Because of the extra time required to perform
the verification, the system runs slower when
programs write data to disk.

Typing VERIFY with no parameters displays the
current state (ON or OFF) of the verify feature.

Note: VERIFY is not supported with data
written to a network disk.

Example: The following example sets VERIFY ON.

A>verify on

To display the current state of VERIFY, type:

A>verify

The result is:

VERIFY is on
A>

7-187

VOL (Volume)
Command

Purpose: Displays the disk volume label of the specified drive.

Format: VOL [d:]

Type: Internal External

***

Remarks: If you do not specify a drive, the default drive is
assumed.

Example: To display the volume label of drive A, type: A.

A>vol

The result is:

Volume in drive A is MYDISK
A>

If drive A has no label, the result is:

Volume in drive A has no label

7-188

Chapter 8. The Line Editor (EDLIN)

Contents

Introduction 8-3

How to Start the EDLIN Program 8-5

Editing an Existing File 8-5

Editing a New File 8-6

The EDLIN Command Parameters 8-7

The EDLIN Commands 8-9

Information Common to All EDLIN

Commands 8-9

A (Append Lines) Command 8-11

C (Copy Lines) Command 8-12

D (Delete Lines) Command 8-13

Edit Line Command 8-16

E (End Edit) Command 8-18

I (Insert Lines) Command 8-19

L (List Lines) Command 8-22

M (Move Lines) Command 8-25

P (Page) Command 8-26

Q (Quit Edit) Command 8-27

R (Replace Text) Command 8-28

S (Search Text) Command 8-31

8-1

T (Transfer Lines) Command 8-34

W (Write Lines) Command 8-35

8-2

Introduction

This chapter describes how to use the Line Editor
(EDLIN) program.

You can use the Line Editor (EDLIN) to create,
change, and display source files or text files. Source
files are unassembled programs in source language
format. Text files appear in a legible format.

EDLIN is a line text editor that you can use to:

• Create new source files and save them

• Update existing files and save both the updated
and original files

• Delete, edit, insert, and display lines

• Search for, delete, or replace text within one or
more lines

The text of files created or edited by EDLIN is divided
into lines of varying length, up to 253 characters per
line.

Line numbers are generated and displayed by EDLIN
during the editing process, but are not actually present
in the saved file.

8-3

When you insert lines, all line numbers following the
inserted text advance automatically by the number of
lines inserted. When you delete lines, all line numbers
following the deleted text decrease automatically by
the number of lines deleted. Consequently, line
numbers always go consecutively from 1 through the
last line number.

Note: EDLIN erases the original backup copy
(.BAK) of the file when you issue an E (end edit)
command, or if the disk space is required during
the editing session to satisfy a W (write lines)
command.

8-4

How to Start the EDLIN Program

To start EDLIN, type:

\d:]\pathEDUN U:]^/?]filenamef.^/!!/RJ

Editing an Existing File

If the specified file exists on the designated or default
drive, the file is loaded into memory until memory is
75% full. If the entire file is loaded, the following
message and prompt is displayed:

End of input file

You can then edit the file.

Note: If you have not used the /B parameter,
EDLIN will stop loading the file when the first
Ctrl-Z is encountered in the file's text. If you wish
to edit a file that is known to contain embedded
Ctrl-Z characters (end-of-file marks), you should
use the /B parameter. EDLIN then processes the
entire file regardless of any embedded end-of-file
marks.

Notice that the prompt for EDLIN is an asterisk (*).

If the entire file cannot be loaded into memory,
EDLIN loads lines until memory is 75% full, then
displays the * prompt. You can then edit the portion
of the file that is in memory.

To edit the remainder of the file, you must write some
of the edited lines to disk to free memory so that you
can load unedited lines from disk into memory. Refer
to the Append Lines and Write Lines commands in
this chapter for the procedure.

8-5

Editing a New File

If the specified file does not exist on the drive, a new
file is opened with the specified name. The following
message and prompt are displayed:

New file
*

Begin creating the file by entering the desired lines of
text. To begin entering text, enter an I command to
insert lines.

When you have completed the editing session, you can
save the file using the End Edit command. The End
Edit command is discussed in this chapter in the
section called "The EDLIN Commands." The new file
is saved with the filename and extension you specified
in the EDLIN command when you first opened the
file.

Note: If you edit an existing file, when you end
the edit session with the End Edit command, the
original file is saved with an extension of .BAK.
You cannot edit a file with a filename extension
of .BAK with EDLIN because the system
assumes it is a backup file. If you find it necessary
to edit such a file, rename the file to another
extension; then start EDLIN and specify the new
name.

8-6

The EDLIN Command Parameters

Parameter

Definition

line

Denotes when you must specify a line
number.

There are three possible entries that
you can make using this parameter:

1 . Enter a decimal integer from
1-65529. If you specify a
number greater than the number
of lines in memory, the line is
added after the last line.

Line numbers must be separated
from each other by a comma or
space.

2. Enter a pound sign (#) to
specify the line after the last line
in memory. Entering a # has the
same effect as specifying a
number greater than the number
of lines in memory.

8-7

Parameter

Definition

line

3. Enter a period (.) to specify the
current line.

The current line indicates the
location of the last change to the
file, but it is not necessarily the
last line displayed. The current
line is marked by an asterisk (*)
between the line number and
the first character of text in the
line. For example:

10:*FIRST CHARACTER OF TEXT

Denotes when you must specify lines.

Enter the number of lines that you
want to write to disk or load from disk.

You only use this parameter with the
Write Lines and Append Lines
commands. These commands are
meaningful only if the file to be edited
is too large to fit in memory.

string

Denotes when you must enter one or
more characters to represent text to be
found, replaced, deleted, or to replace
other text.

You only use this parameter with the
Search Text and Replace Text
commands. ]

8-8

The EDLIN Commands

This section describes the EDLIN commands and tells
how to use them. The commands are in alphabetic
order, each with its purpose, format and remarks.
Examples are provided where appropriate.

Information Common to All EDLIN
Commands

The following information applies to all EDLIN
commands:

• With the exception of the Edit Line command, all
commands are a single letter.

• With the exception of the End Edit and Quit Edit
commands, commands are usually preceded
and/or followed by parameters.

• Enter commands and string parameters in
uppercase, or lowercase, or a combination of
both.

• Separate commands and parameters with
delimiters for readability; however, a delimiter is
only required between two adjacent line numbers.
Remember, delimiters are spaces or commas.

• Commands become effective only after you press
the Enter key.

• Stop commands by pressing the Ctrl-Break keys.

• For commands producing a large amount of
output, press Ctrl-Num Lock to suspend the
display so that you can read it before it scrolls
away. Press any other character to restart the
display.

8-9

Use the control keys and DOS editing keys,
described in the DOS User's Guide, while using
EDLIN. They are very useful for editing within a
line, while the EDLIN commands can be used for
editing operations on entire lines.

The prompt from EDLIN is an asterisk (*).

It is possible to refer to line numbers relative to
the current line. Use a minus (-) sign and a
number to indicate a line before the current line.
Use a plus (+) sign and a number to indicate a
line after the current line. For example:

-10,-s-lOL

This command displays 1 lines before the
current line, the current line, and 10 lines after
the current line.

Multiple commands can be entered on one
command line. When you enter the command to
edit a single line using [line], you must use a
semicolon to separate the commands on the line.
In the case of the Search or Replace commands
the [string] can be terminated by Ctrl-Z (F6)
instead of the Enter key. Otherwise, one
command can follow another without any special
delimiting characters. For example:

15;-5,+5L

edits line 15 and then displays lines 10 through
20 on the screen.

Control characters can be inserted into the text,
or can be used in the strings for the Search and
Replace text commands. To enter a control
character, press Ctrl-V, then enter the desired
control character in uppercase. For example, the
sequence Ctrl-V, followed by Z generates the
control character Ctrl-Z.

8-10

A (Append Lines)
Command

Purpose: Adds the specified number of lines from disk to the
file being edited in memory. The lines are added at
the end of the current lines in memory.

Format: [n]A

Remarks: This command is only meaningful if the file being
edited is too large to fit in memory. As many lines
as possible are read into memory for editing when
you start EDLIN. If you do not specify the number
of lines, lines are appended to memory until available
memory is 75% full. No action is taken if available
memory is already 75% full.

To edit the remainder of the file that will not fit into
memory, you must write edited lines in memory to
disk before you can load unedited lines from disk
into memory by using the Append Lines command.
Refer to the Write Lines command for information
on how to write edited lines to disk.

The message End of input file is displayed when the
Append Lines command has read the last line of the
file into memory.

8-11

C (Copy Lines)
Command

Purpose: Copies the lines in the specified range to the line
number specified by the third parameter. The new
data is placed ahead of the line that was specified in
the third parameter. This third parameter is not
optional. The operation is repeated the number of
times specified in count.

Format : [ line] , [ line] , line[, count]C

Remarks: The parameter count defaults to 1. To repeat text,
specify the number of times the operation is to be
performed in count. If the first parameter or the
second parameter is omitted, the default is the
current line. This effectively copies the current line
to the specified line. The file is renumbered
accordingly. The first of the copied lines becomes the
current line. For example:

1,5,8C

copies lines 1 through 5 to line 8. Line 8 becomes
the current line.

The line numbers must not overlap or an error is
reported. Also, the characters - and + are not
allowed in the count field.

8-12

D (Delete Lines)
Command

Purpose: Deletes a specified range of lines.

Format: [line][,line] D

Remarks: The line following the deleted range becomes the
current line, even if the deleted range includes the
last line in memory. The current line and any
following lines are renumbered.

If you omit the first parameter, as in:

,1 ineD

deletion starts with the current line and ends with
the line specified by the second parameter. The
beginning comma is required to indicate the omitted
first parameter.

If you omit the second parameter, as in:

lineD or line,D

only the one specified line is deleted. If you omit
both parameters, as in:

only the current line is deleted, and the line that
follows becomes the current line.

Example: Assume that you want to edit the following file. The
current line is line 22.

8-13

D (Delete Lines)
Command

This is a sample file used to demonstrate
line deletion and dynamic
line number generation.

20
21
22
23

See what happens to the lines
and line numbers when lines are
^deleted.
See how easy this is to use.

If you want to delete a range of lines, from 3-20,
enter:

3,20D

The result is:

This is a sample file used to demonstrate
line deletion and dynamic
*and line numbers when lines are
deleted.
See how easy this is to use.

Lines 3-20 are deleted from the file. Lines 21-23
are renumbered to 3-5. Line 3 becomes the current
line. If you want to delete the current and the
following line, enter:

,4D

The result is:

This is a sample file used to demonstrate
line deletion and dynamic
*See how easy this is to use.

Lines 3 and 4 are deleted from the file. Line 5 is
renumbered to 3. Line 3 is still the current line, but
now it has different text.

8-14

D (Delete Lines)
Command

If you want to delete a single line, say line 2, enter:

The result is:

1: This is a sample file used to demonstrate
2:*See how easy this is to use.

Line 2 is deleted. Line 3 is renumbered to 2. The
new line 2 becomes the current line. If you want to
delete only the current line, enter:

The result is:

l:*This is a sample file used to demonstrate

The current line, line 2, is deleted. The new line 1
becomes the current line.

8-15

Edit Line
Command

Purpose: Allows you to edit a line of text. You must enter the
line number of the line to be edited, or enter a period
(.) to indicate the current line.

Format: [line]

Remarks: If you just press Enter, you specify that the line after
the current line is to be edited. The line number and
its text are displayed and the line number is repeated
on the line below.

You can use the control keys and the editing keys,
described in the DOS User's Guide, to edit the line,
or you can replace the entire line by typing new text.
When you press the Enter key, the edited line is
placed in the file and becomes the current line.

If you decide not to save the changed line, press
either Esc or Ctrl-Break instead of Enter. The
original line remains unchanged. Pressing the Enter
key with the cursor at the beginning of the line has
the same effect as pressing Esc or Ctrl-Break.

If the cursor is in any position other than the
beginning or the end of a line, pressing Enter erases
the rest of the line.

Example: Assume that you want to edit line 6. The following
display would appear on the screen:

6: This is a sample unedited line.
6:

The first line is your request to edit line 6, followed
by the two-line display response.

8-16

Edit Line
Command

If you want to move the cursor to the letter u, press
F2 and enter:

The result is:

*6
6: This is a sample unedited line.
6: This is a sample

If you want to delete the next two characters and
keep the remainder of the line, press Del twice; then
press F3.

The result is:

*6
6: This is a sample unedited line.
6: This is a sample edited line.

Now you can take one of the following actions:

• Press Enter to save the changed line.

• Extend the changed line by typing more text.
You are automatically in insert mode when the
cursor is at the end of a line.

• Press F5 to do additional editing to the changed
line without changing the original line.

• Press Esc or Ctrl-Break to cancel the changes
you made to the line. The original contents of
the line are preserved.

8-17

E (End Edit)
Command

Purpose: Ends EDLIN and saves the edited file.

Format: E

Remarks: The edited file is saved by writing it to the drive and
filename specified when you started EDLIN.

The original file, the one specified when EDLIN was
started, is given a .BAK filename extension. A
.BAK file will not be created if there is no original
file; that is, if you created a new file instead of
updating an old file during the editing session.

EDLIN returns to the DOS command processor,
which displays the command prompt.

Be sure your disk has enough free space to save the
entire file. If your disk does not have enough free
space, only a portion of the file is saved. The portion
in memory that is not written to disk is lost. In this
case, your original file is not renamed to .BAK, and
the portion of data that was written to disk will have
a filename extension of $$$.

EDLIN appends a carriage return, line feed sequence
to the end of the file, if they were not already
present, to delimit the last line of text in the file.
Also, a Ctrl-Z character is added as the last character
in the saved file. This serves as an end-of-file mark.

8-18

I (Insert Lines)
Command

Purpose: Inserts lines of text immediately before the specified
line. When you create a new file, you must enter the
Insert Lines command before text can be inserted.

Format: [line]\

Remarks: If you do not specify line, or if you specify line as a
period (.), the insert is made immediately before the
current line. If the line number you specify is greater
than the highest existing line number, or if you
specify # as the line number, the insertion is made
after the last line in memory.

EDLIN displays the appropriate line number so that
you can enter more lines, ending each line by
pressing Enter. During the insert mode of operation,
successive line numbers appear automatically each
time Enter is pressed.

You must press Ctrl-Break to discontinue the insert
mode of operation.

The line that follows the inserted lines becomes the
current line, even if the inserted lines are added to
the end of the lines in memory. The current line and
any remaining lines are renumbered.

Example: Assume that you want to edit the following file.
Line 2 is the current line.

This is a sample file used to demonstrate
*line deletion
and dynamic line number generation.

If you want to insert text before line 3, the entry
and immediate response look like this:

8-19

I (Insert Lines)
Command

■31

Now, if you want to insert two new lines of text,
enter:

*3 I

3:*First new line of text
4:*Second new line of text
5:*

and press Ctrl-Break.

The original line 3 is now renumbered to line 5.

If you display the file with a List Lines command, the
file looks like this:

This is a sample file used to demonstrate
line deletion
First new line of text
Second new line of text
*and dynamic line number generation.

8-20

I (Insert Lines)
Command

If the two lines that were inserted had been placed
at the beginning of the file, the screen would look
like this:

First new 1 ine of text
Second new line of text
*This is a sample file used to demonstrate
1 ine deletion
and dynamic line number generation.

If the two lines that were inserted had been placed
immediately before the current line (2 I or . I or I),
the screen would look like this:

This is a sample file used to demonstrate
First new 1 ine of text
Second new line of text
* 1 ine deletion
and dynamic line number generation.

If the two inserted lines had been placed at the end
of the file (4 I or # I), the screen would look like
this:

This is a sample file used to demonstrate

line deletion

and dynamic line number generation.

First new 1 ine of text

Second new line of text

8-21

L (List Lines)
Command

Purpose: Displays a specified range of lines. The current line
remains unchanged.

Format: [line][,line]L

Remarks: Default values are provided if either one or both of
the parameters are omitted. If you omit the first
parameter, as in:

,1 ineL

the display starts 1 1 lines before the current line and
ends with the specified line. The beginning comma is
required to indicate the omitted first parameter.

Note: If the specified line is more than 1 1 lines
before the current line, the display is the same as
if you omitted both parameters. (An example is
provided in this section showing both
parameters omitted.)

If you omit the second parameter, as in:

lineL or line,L

a total of 23 lines are displayed, starting with the
specified line.

If you omit both parameters, as in:

a total of 23 lines are displayed-the 1 1 lines before
the current line, the current line, and the 1 1 lines
after the current line. If there aren't 1 1 lines before
the current line, then extra lines are displayed after
the current line to make a total of 23 lines.

8-22

L (List Lines)
Command

Example: Assume that you want to edit the following file.
Line 15 is the current line.

This is a sample file used to demonstrate
line deletion and dynamic
line number generation.

15:*This is the current line (note the asterisk)

25
26
27

See what happens to the lines
and line numbers when lines are
deleted.

If you want to display a range of lines, from 3-25,
enter:

3,25L

The screen looks like this:

3: line number generation.

15:*This is the current line (note the asterisk)

25: See what happens to the lines

If you want to display the first three lines, enter:

1,3L

The screen looks like this:

8-23

L (List Lines)
Command

This is a sample file used to demonstrate
line deletion and dynamic
line number generation.

If you want to display 23 lines of the file, starting
with line 3, enter:

The screen looks like this:

3: line number generation.

15:*This is the current line (note the asterisk)

25: See what happens to the lines

If you want to display 23 lines centered around the
current line, enter:

The screen looks like this:

4: Fourth 1 ine of text
5: Fifth line of text

15:*This is the current line (note the asterisk)

25: See what happens to the lines
26: and line numbers when lines are

8-24

M (Move Lines)
Command

Purpose: Moves the range of lines specified by the first two
line parameters ahead of the line specified in the
third line parameter. The third parameter is not
optional.

Format: [line],[line],lineM

Remarks: Use this command to move a block of data from one
location in the file to another. If the first or second
line parameter is omitted, it will default to the
current line. After the move, the first of the moved
lines becomes the current line. The lines are
renumbered according to the direction of the move.
For example:

,+25,100M

moves the data from the current line plus 25 lines to
line 100. If the arguments overfap an entry error is
reported.

8-25

P (Page)
Command

Purpose: Lists the specified block of lines.

Format: [line][,line]P

Remarks: If the first line parameter is omitted, it defaults to the
current line plus one. If the second line parameter is
omitted, 23 lines are listed. The new current line
becomes the last line displayed by the Page
command and is marked with an asterisk. This
command pages through a file displaying 23 lines at a
time. It differs from the List Lines command in that
it changes the current line.

8-26

Q (Quit Edit)
Command

Purpose: Quits the editing session without saving any changes
you may have entered.

Format: Q

Remarks: EDLIN prompts you to make sure you really don't
want to save the changes.

Enter Y if you want to quit the editing session. No
editing changes are saved and no .BAK file is
created. Refer to the End Edit command for
information about the .BAK file.

Enter N, or any other character, if you want to
continue the editing session.

Example: When you type the letter Q, the following is
displayed:
Q

Abort edit (Y/N)?

8-27

R (Replace Text)
Command

Purpose: Replaces all occurrences of the first string in the
specified range of lines with the second string.

Notes:

1 . If you omit the second string, Replace Text
deletes all occurrences of the first string within
the specified range of lines. If you omit both
strings, EDLIN re-uses the search string
entered with the most recent (previous) S or R
command, and the Replace Text string entered
with the last R command.

2. This command uses the F6 key as normally
setup by DOS. If you have changed the meaning
of the F6 key through "Extended Keyboard
Control" (see Chapter 3 of the DOS Technical
Reference manual), you should press Ctrl-Z
where F6 is referred to below.

EDLIN displays the changed lines each time they are
changed. The last line changed becomes the current
line.

Format: [line][,line] [?]R[string][<F6> string]

Remarks: You can specify the optional parameter ? to request a
prompt (O.K.?) after each display of a modified line.
Press Y or the Enter key if you want to keep the
modification.

Enter any other character if you don't want the
modification. In either case, the search continues for
further occurrences of the first string within the
range of lines, including multiple occurrences within
the same line.

8-28

R (Replace Text)
Command

Defaults occur if either one or both of the line
parameters are missing.

If you omit the first line, the search begins with the
line after the current line. If you omit the second
line, the search ends with the last line in memory. If
you omit both line parameters, the system searches
from the line following the current line to the last
line in memory.

Note: The first string begins with .the character
in the position immediately following the R, and
continues until you press F6 or Ctrl-Z (or the
Enter key if the second string is omitted).

The second string begins immediately after you
press F6 or Ctrl-Z and continues until you press
Enter.

Example: Assume that you want to edit the following file.
Line 7 is the current line.

This is a sample file
used to demonstrate
the Replace and Search Text commands
This includes the
optional parameter ?
and required string
*parameter.

8-29

R (Replace Text)
Command

To replace all occurrences of and with or in the lines
in memory, enter:

I ,7 Rand

Then press F6, type or, and press Enter.

The result is:

the Replace or Search Text commands
the Replace or Search Text commors.
or required string

Line 6 becomes the current line in the file, because
line 6 was the last line changed. Notice that lines 1 ,
2, 4, 5, and 7 are not displayed because they were
not changed.

Greater selectivity can be achieved by requesting a
prompt (by using the ? parameter) after each display
of a modified line. If you request a prompt, the
screen looks like this:

*1,7 ? Rand (Press F6 , type or, and press Enter)
3: the Replace or Search Text commands

O.K.? Y

3: the Replace or Search Text commors

O.K.? N

6: or required string

O.K.? Y

Lines 3 and 6 are displayed like this:

3: the Replace or Search Text commands.
6: or required string

8-30

S (Search Text)
Command

Purpose: Searches a specified range of lines in order to locate
a specified string.

Format: [line][,line] [^[string]

Remarks: The first line to contain the specified string is

displayed and the search ends (unless you use the ?
parameter). The first line found that contains the
specified string becomes the current line.

Note: The Search command always searches for
the exact same character in text. That is, it
searches for UPPERCASE if you enter
UPPERCASE, and lowercase if you enter
lowercase.

You should specify the optional parameter ? if you
would like a prompt (O.K.?) after each display of a
line containing the specified string.

If you do not enter a string, the S command uses the
last search string entered on a Replace or Search
command. If the specified string is not found, the
search ends and the message Not found is displayed.
The current line remains unchanged. If you enter Y
or press the Enter key, the line that matches the
specified string becomes the current line and the
search ends. Enter any other character to continue
the search until another string is found, or until all
lines within the range are searched. Once all the
lines within the range are searched, the Not found
message is displayed.

The system provides default values if you omit the
first, second, or both line parameters. If you omit
the first line parameter, the system defaults to the

8-31

S (Search Text)
Command

line following the current line. If you omit the
second line parameter, the system defaults to the last
line in memory. If you omit both line parameters,
the system searches from the line following the
current line to the last line in memory.

Notes:

1 . The string begins with the character in the
position immediately following the S and
continues until you end the string by pressing
the Enter key.

2. If you wish to place more than one command on
a line containing a Search Text command, the
Search Text command should end in a Ctrl-Z
(F6), and the next command should begin in the
following character position.

Example: Assume that you want to edit the following file.
Line 7 is the current line.

This is a sample file
used to demonstrate
the Search Text command,
This includes the
optional parameter ?
and required string
'parameter.

If you want to search for the first occurrence of and
in the file, enter:

1,7 Sand

or
1 , Sand

or
ISand

8-32

S (Search Text)
Command

The result is:

3: the Search Text command.

The and is part of the word command. Notice that
line 3 becomes the current line in the file.

Perhaps this is not the and you were looking for. To
continue the search, simply enter the letter S and
press Enter. The search continues with the line
following the current line (the line just found).

The screen looks like this:

*1,7 Sand

3: the Search Text command.
*S

6: and required string

Line 6 now becomes the current line in the file.

You can also search for strings by requesting a
prompt (by means of the ? parameter) after each
display of a matching line. In this case, the screen
looks like this:

*1,7 ? Sand

3: the Search Text command.
O.K.? N

6: and required string
O.K.? Y

8-33

T (Transfer Lines)
Command

Purpose: Transfers (merges) the contents of a specified file
into the file currently being edited.

Format: [line]T:[d:]filename

Remarks: The filename contents are inserted ahead of the line
in the file being edited. If line is omitted, the current
line is used.

Note: The file being merged is read from the
current directory of the specified or default
drive. If a path was specified when you issued
the EDLIN command, that path becomes the
current directory for that drive for the duration
of the EDLIN session, and any Transfer Lines
commands for that drive must be satisfied from
the same directory.

8-34

W (Write Lines)
Command

Purpose: Writes a specified number of lines to disk from the
lines being edited in memory. Lines are written
beginning with line number 1 .

Format: [n]W

Remarks: This command is only meaningful if the file you are
editing is too large to fit in memory. When you start
EDLIN, it reads lines into memory until memory is
75% full.

To edit the remainder of the file not in memory, you
must write edited lines in memory to disk. Then you
can load additional unedited lines from disk into
memory by using the Append Lines command.

Note: If you do not specify the number of lines,
lines are written until 25 % of available memory
is used. No action is taken if available memory
is already less than 25 % used. All lines are
renumbered so that the first remaining line
becomes number 1 .

8-35

Notes:

8-36

Chapter 9. The Linker (LINK) Program

Contents

Introduction 9-3

Files 9-4

Input Files 9-4

Output Files 9-5

VM.TMP (Temporary File) 9-5

Definitions 9-6

Segment 9-6

Group 9-7

Class 9-7

Command Prompts 9-7

Detailed Descriptions of the Command Prompts . . 9-9

Object Modules [.OBJ]: 9-9

Run File [filename.EXE]: 9-10

List File [NUL.MAP]: 9-10

Libraries [.LIB]: 9-12

Linker Parameters 9-14

/DSALLOCATION 9-14

/HIGH 9-14

/LINE 9-15

/MAP 9-15

/PAUSE 9-15

/STACK:size 9-16

/X 9-16

/O 9-17

How to Start the Linker Program 9-17

Before You Begin 9-17

Option 1 - Console Responses 9-17

Option 2 - Command Line 9-18

Option 3 - Automatic Responses 9-21

9-1

Example Linker Session 9-23

How to Determine the Absolute Address of a
Segment 9-26

Messages 9-27

9-2

Introduction

The linker (LINK) program:

• Combines separately produced object modules

• Searches library files for definitions of unresolved
external references

• Resolves external cross-references

• Produces a printable listing that shows the
resolution of external references and error
messages

• Produces a relocatable load module

The LINK program resides on your DOS
Supplemental Program Diskette. This chapter shows
you how to use LINK. Read all of this chapter before
you start LINK.

9-3

Files

The linker processes input, output, and temporary
files.

Input Files

Type

Default
.ext

Override
.ext

Produced by

Object

.OBJ

Yes

Compiler 1 or
MACRO Assembler

Library

.LIB

Yes

Compiler and user

Automatic
Response

(None)

N/A*

User

Figure 9-1 Input Files Used by the Linker

r N/A - Not applicable,

1 One of the optional compiler packages available for use with the IBM
Personal Computer DOS.

9-4

Output Files

Type

Default
.ext

Override
.ext

Used by

Listing
Run

.MAP
.EXE

Yes

User

Relocatable loader
(COMMAND.COM)

Figure 9-2

Output Files Used by the Linker

VM.TMP (Temporary File)

LINK uses as much memory as is available to hold the
data that defines the load module being created. If the
module is too large to be processed with the available
amount of memory, the linker may need additional
memory space. If this happens, a temporary file called
VM.TMP is created on the DOS default drive.

When the overflow to the VM.TMP file has begun, the
linker displays the following message:

VM.TMP has been created

Do not change diskette in drive x

If the VM.TMP file has been created on diskette, you
should not remove the diskette until LINK ends.
When LINK ends, it erases the VM.TMP file.

If the DOS default drive already has a file by the name
of VM.TMP, it is deleted by LINK and a new file is

9-5

allocated; the contents of the previous file are
destroyed. Therefore, you should avoid using
VM.TMP as one of your own filenames.

Definitions

Segment, group, and class are terms that appear in this
chapter and in some of the messages in Appendix A.
These terms describe the underlying function of
LINK. An understanding of the concepts that define
these terms provides a basic understanding of the way
LINK works.

Segment

A segment is a contiguous area of memory up to 64K
bytes in length. A segment may be located anywhere
in memory on a paragraph (16-byte) boundary. Each
of the four segment registers defines a segment. The
segments can overlap. The contents of a segment are
addressed by a segment register/offset pair.

The contents of various portions of the segment are
determined when machine language is generated.

Neither size nor location is necessarily fixed by the
compiler or assembler because this portion of the
segment may be combined at link time with other
portions forming a single segment.

A program's ultimate location in memory is
determined at load time by the relocation loader
facility provided in COMMAND.COM, based on
whether you specified the /HIGH parameter. The
/HIGH parameter is discussed later in this chapter.

9-6

Group

Class

A group is a collection of segments that fit together
within a 64K byte segment of memory. The segments
are named to the group by the assembler or compiler.
A program may consist of one or more groups.

The group is used for addressing segments in memory.
The various portions of segments within the group are
addressed by a segment base pointer plus an offset.

A class is a collection of segments. The naming of
segments to a class affects the order and relative
placement of segments in memory. The class name is
specified by the assembler or compiler. All portions
assigned to the same class name are loaded into
memory contiguously.

The segments are ordered within a class in the order
that the linker encounters the segments in the object
files. One class precedes another in memory only if a
segment for the first class precedes all segments for
the second class in the input to LINK. Classes are not
restricted in size.

Command Prompts

After you start the linker session, you receive a series
of four prompts. You can respond to these prompts
from the keyboard, on the command line, or by using a
special diskette file called an automatic response file.
An example of an automatic response file is provided
in this chapter.

9-7

LINK prompts you for the names of the object, run,
list, and library files. When the session is finished,
LINK returns to DOS and the DOS prompt is
displayed. If linking is unsuccessful, LINK displays a
message.

The prompts are described in order of their

ippearance on the screen. Defaults are sho\vu m

' VV 1A

square brackets ([ ]) after the prompt. In the response
column of the table, square brackets indicate optional
entries. Object Modules is the only prompt that
requires a response from you.

PROMPT

RESPONSE

Object Modules [.OBJ]:

[d: ][path]filename[.ext]

[ + • [d: ] [path]filename[
.ext]]...

Run File [filename.EXE]:

[ d: ] [path] [filename[ . ext] ]

List File [NUL.MAP]:

[d:][path][filename[.ext]]

Libraries [.LIB]:

[d:][ [path]filename[ . ext] ]

[+.[d: ] [[paihlfilename
[.ext]]]...

Notes:

1 . If you enter a filename without specifying the
drive, the default drive is assumed. If you enter a
filename without specifying the path, the default
path is assumed. The libraries prompt is an
exception-the linker will look for the libraries on
the default drive and if not found, look on the
drive specified by the compiler.

2. You can end the linker session prior to its normal
end by pressing Ctrl-Break.

9-8

Detailed Descriptions of the Command
Prompts

The following detailed descriptions contain
information about the responses that you can enter to
the prompts.

Object Modules [.OBJ]:

Enter one or more file locations for the object
modules to be linked. Multiple file locations must be
separated by single plus (+) signs or blanks. If the
extension is omitted from any filename, LINK
assumes the filename extension .OBJ. If an object
module has a different filename extension, the
extension must be specified. Object filenames can not
begin with the @ symbol ( @ is reserved for using an
automatic response file).

LINK loads segments into classes in the order
encountered.

If you specify an object module on a diskette drive,
but LINK cannot locate the file, it displays the
following prompt:

Cannot find file object module
change diskette <press ENTER>

If you specify an object module on a non-removable
media (like a fixed disk), the linker session ends with
the following message:

Cannot find file object module

You should insert the diskette containing the
requested module. This permits .OBJ files from
several diskettes to be included. On a single-drive
system, diskette exchanging can be done safely only if

9-9

VM.TMP has not been opened. As explained in the
discussion of the VM.TMP file earlier in this chapter,
a message will indicate if VM.TMP has been opened.

Important: If a VM.TMP file has been opened on a
diskette, you should not remove the diskette containing
the VM.TMP file.

After a VM.TMP file has been opened, if you
specified an object module on the same disk that
VM.TMP is on and LINK cannot find it, the linker
session ends with the message:

Cannot find file object module

Run File [fiIename.EXE]:

The file specification you enter is created to store the
run (executable) file that results from the LINK
session. All run files receive the filename extension
.EXE, even if you specify another extension. If you
specify another extension, it is ignored.

The default filename for the run file prompt is the first
filename specified on the object module prompt.

You can specify just a drive letter, or a path on the run
file prompt. This changes the place where the run file
fiIename.EXE is placed.

List File [NUL.MAP]:

The linker list file is sometimes called the linker map.

The list file is not created unless you specifically
request it. You can request it by overriding the default
with a drive letter, path, or filename[.ext]. If you do
not include a filename extension, the default extension
.MAP is used. If you do not enter anything, the DOS
reserved filename NUL specifies that no list file is
created.

9-10

The list file contains an entry for each segment in the
input (object) modules. Each entry also shows the
offset (addressing) in the run file.

You can specify just a drive letter or a path on the list
file prompt. This changes the place where the list file
is placed.

Important: If the list file is allocated to a file on
diskette, that diskette must not be removed until the
LINK has ended.

Note: There is one exception. If /P is specified,
the diskette containing the list file may be
removed while the .EXE file is being written.
The linker prompts you to put back the diskette
containing the list file when it finishes writing the
.EXE file.

If you specify an object module on the same diskette
drive as the diskette drive to which the list file is
allocated, and LINK cannot find the object module,
the linker session ends with the message:

Cannot find file object module

To avoid generating the list file on a diskette, you can
specify the display or printer as the list file device.
For example:

List File [NUL.MAP]: CON

If you direct the output to your display, you can also
print a copy of the output by pressing Ctrl-PrtSc.

9-11

Libraries [.LIB]:

You may either list the file locations for your libraries,
or just press the Enter key. If you press the Enter key,
LINK defaults to the library provided as part of the
Compiler package.

T1ip> T TXTl<r nrrxarum Inolrc fr»r thf* Cf\mr\Ue±r r^Qplroop

library on the default drive. If it cannot find the library
there, it looks for the library on the drive specified by
the Compiler package. For linking objects from just
the MACRO Assembler, there is no automatic default
library search.

If you answer the library prompt, you specify a list of
drive letters and \path\filename .ext separated by plus
signs (+) or spaces. You can enter from 1 to 16
library file locations. Specifying a drive letter tells
linker to look on that drive instead of the Compiler
package supplied drive for all subsequent libraries on
the library prompt. The automatically searched library
file specifications are conceptually placed at the end of
the response to the library prompt.

LINK searches the library files in the order they are
listed to resolve external references. When LINK
finds the module that defines the external symbol, the
module is processed as another object module.

If two or more libraries have the same filename,
regardless of the location, only the first library in the
list is searched.

When LINK cannot find a library file, it displays a
message like this:

Cannot find library A:library file
Enter new drive letter:

The drive that the indicated library is located on must
be entered.

9-12

The following library prompt responses may be used:

Libraries [.LIB]: B:

Look for compiler. LIB on drive B.

Libraries [.LIB]: B:USERLIB

Look for USERLIB.LIB on drive B and
compiler.LIB on drive A.

Libraries [.LIB]: A:LIB1+LIB2+B:LIB3+A:

Look for LIB 1. LIB and LIB2.LIB on
drive A, LIB3.LIB on drive B, and
compiler.LIB on drive A.

9-13

Linker Parameters

At the end of any of the four linker prompts, you may
specify one or more parameters that instruct the linker
to do something differently. Only the / and first letter
of any parameter are required.

/DSALLOCATION

The /DSALLOCATION (/D) parameter directs
LINK to load all data defined to be in DGROUP at
the high end of the group. If the /HIGH parameter is
specified, (module loaded high), any available storage
below the specifically allocated area within DGROUP
is allocated dynamically by your application. It still is
addressable by the same data space pointer.

Note: The maximum amount of storage which
can be dynamically allocated by the application is
64K-bytes (or the amount actually available)
minus the allocated portion of DGROUP.

If the /DSALLOCATION parameter is not specified,
LINK loads all data defined to be in the group whose
group name is DGROUP at the low end of the group,
beginning at an offset of 0. The only storage thus
referenced by the data space pointer should be that
specifically defined as residing in the group.

All other segments of any type in any GROUP other
than DGROUP are loaded at the low end of their
respective groups, as if the /DSALLOCATION
parameter were not specified.

For certain compiler packages, /DSALLOCATION is
automatically used.

/HIGH

The /HIGH (/H) parameter causes the loader to
place the run image as high as possible in storage. If

9-14

you specify the /HIGH parameter, you tell the linker
to cause the loader to place the run file as high as
possible without overlaying the transient portion of
COMMAND.COM, which occupies the highest area
of storage when loaded. If you do not specify the
/HIGH parameter, the linker directs the loader to
place the run file as low in memory as possible.

The /HIGH parameter is used with the
/DSALLOCATION parameter.

/LINE

For certain IBM Personal Computer language
processors, the /LINE (/L) parameter directs LINK
to include the line numbers and addresses of the
source statements in the input modules in the list file.

/MAP

The /MAP (/M) parameter directs LINK to list all
public (global) symbols defined in the input modules.
For each symbol, LINK lists its value and
segment-offset location in the run file. The symbols
are listed at the end of the list file.

/PAUSE

The /PAUSE (/P) parameter tells LINK to display a
message to you as follows:

About to generate .EXE file
Change disks <press ENTER>

This message allows you to insert the diskette that is
to contain the run file.

9-15

/STACKisize

The size entry is any positive decimal value up to
65536 bytes. This value is used to override the size of
the stack that the MACRO Assembler or compiler has
provided for the load module being created. If the size
of the stack is too small, the results of executing the
resulting load module are unpredictable.

If you do not specify /STACK (/S), the orginal stack
size provided by the MACRO Assembler or compiler
is used. This parameter can be used to reduce the
stack size provided by the application only if the
original stack has uninitialized data. In any case, it
may increase the stack up to the 64K limit.

If the stack size is an odd number, either on the /S
parameter or in the application's definition of the
stack, LINK subtracts one to force the stack words to
be on an even boundary for better efficiency when
running on the 80286.

At least one input (object) module must contain a
stack allocation statement, unless you plan to use the
EXE2BIN program. This is automatically provided by
compilers. For the MACRO Assembler, the source
must contain a SEGMENT command that has the
combine type of STACK. If a stack allocation
statement was not provided, LINK returns the
message Warning: No Stack statement.

Use the /X parameter at runtime to adjust the total
number of segments that an .EXE file can contain.
You can vary the limit from to 1024. The default is
256 segments. This limit represents the number of
distinct segments from all sources (object files and
libraries) that the .EXE may contain.

Although the limit on the total number of segments
may be set as high as 1024, the limit on the total

9-16

number of segments that are not absolute segments is
1000. For a definition of absolute segments, see the
assembler manual.

To link object modules created by version 1 of the
Pascal compiler or version 1 of the FORTRAN
compiler using the 2.30 linker, specify the /O (old)
switch.

How to Start the Linker Program

Before You Begin

• Make sure the files you use for linking are on the
appropriate disks.

• Make sure you have enough free space on your
disks to contain your files and any generated data.

You can start the linker program by using one of three
options:

Option 1 - Console Responses

From your keyboard, type:

LINK

The linker is loaded into memory and displays a series
of four prompts, one at a time, to which you must
enter the requested responses. (Detailed descriptions
of the responses that you can make to the prompts are
discussed in this chapter.)

9-17

If you enter a wrong response, such as an incorrectly
spelled filename, you must press Ctrl-Break to exit
LINK, then restart LINK. If the response in error has
been typed but you haven't pressed Enter yet, you can
delete the wrong characters (on that line only).

An example of a linker session using the console
response option is provided in this chapter in the
section called "Example Linker Session."

As soon as you have entered the last filename, the
linker begins to run. If the linker finds any errors, it
displays the errors on the screen as well as in the
listing file.

Note: After any of these responses, before
pressing Enter, you can continue the response
with a comma and the answer to what would be
the next prompt, without having to wait for that
prompt. If you end any with the semicolon (;),
the remaining responses are all assumed to be the
default. Processing begins immediately with no
further prompting.

Option 2 - Command Line

From your keyboard, type:

LINK objlist, runfile, map file, liblist [parm ]...;

objlist is a list of object modules separated by
spaces or plus signs ( + )•

run file is the name you want to give the run file.

map file is the name you want to give the linker map.

liblist is a list of the libraries to be used, separated
by plus signs ( + ) or spaces.

parm is an optional linker parameter. Each

parameter must begin with a slash (/).

9-18

The linker is loaded and immediately performs the
tasks indicated by the command line.

When you use this command line, the prompts
described in Option 1 are not displayed if you
specified an entry for all four files or if the command
line ends with a semicolon.

If an incomplete list is given and no semicolon is used,
the linker prompts for the remaining unspecified files.

Each prompt displays its default, which is accepted by
pressing the Enter key, or overridden with an explicit
filename or device name. However, if an incomplete
list is given and the command line is terminated with a
final semicolon, the unspecified files default without
further prompting. The parms are never prompted for,
but may be added to the end of the command line or
to any file specification given in response to a prompt.

Certain variations of this command line are permitted.

Examples:

LINK module

The object module is MODULE.OBJ. A
prompt is given, showing the default of
MODULE.EXE. After the response is
entered, a prompt is given showing the
default of NUL.MAP. After the response
is given, a prompt is displayed showing
the default extension of .LIB.

LINK module;

If the semicolon is added, no further
prompts are displayed. The object
module of MODULE.OBJ is linked, the
run file is put into MODULE.EXE, and
no list file is produced.

9-19

LINK module,,;

This is similar to the preceding example,
except the list file is produced in
MODULE.MAP.

LINK module,,

Using the same example, but without the
semicolon, MODULE. OBJ is linked, and
the run file is produced in
MODULE.EXE, but a prompt is given
with the default of MODULE.MAP.

LINK module„NUL;

No list file is produced. The run file is in
MODULE.EXE. No further prompts are
displayed.

9-20

Option 3 - Automatic Responses

It is often convenient to save responses to the linker
for use at a later time. This is especially useful when
long lists of object modules need to be specified.

Before using this option, you must create the
automatic response file. It contains several lines of
text, each of which is the response to a linker prompt.
These responses must be in the same order as the
linker prompts that were discussed earlier in this
chapter. If desired, a long response to the object
module or libraries prompt may be contained on
several lines by using a plus sign (+) to continue the
same response onto the next line.

To specify an automatic response file, you enter a file
specification preceded by an @ symbol in place of a
prompt response or part of a prompt response. The
prompt is answered by the contents of the diskette
file. The file specification cannot be a reserved DOS
filename.

From your keyboard, type:

LINK @[d:][path\filename\[ext]

Use of the filename extension is optional and can be
any name. There is no default extension.

Use of this option permits the command that starts
LINK to be entered from the keyboard or within a
batch file without requiring any response from you.

9-21

Example

Automatic Response File - RESP1

M0DA+M0DB+M0DC+
MODD+MODE+MODF

Automatic Res n onse hi !e - RLSP2

runf i le/p
printout

Command line

LINK @RESPl+mymod,@RESP2;

Notes:

1. The plus sign at the end of the first line in RESP1
causes the modules listed in the first two lines to
be considered as the input object modules. After
reading RESP1, the linker returns to the
command line and sees +mymod, so it includes
MYMOD.OBJ in the first list of object modules
as well.

2. Each of the above lines ends when you press the
Enter key.

9-22

Example Linker Session

This example shows you the type of information that
is displayed during a linker session.

When you type:

b:link

in response to the DOS prompt, the system responds
with the following messages and prompts, which you
answer as shown:

IBM Personal Computer Linker

Version 2.30 (C)Copyright IBM Corp. 1981, 1982, 1983, 1984

Object Modules [.OBJ]: example
Run File [EXAMPLE.EXE]: /map
List File [NUL.MAP]: prn/line
Libraries [.LIB]:

Notes:

1 . By specifying /map, you get both an alphabetic
listing and a chronological listing of public
symbols.

2. By responding prn to the list file prompt, you send
your output to the printer.

3. By specifying the /LINE parameter, LINK gives
a listing of all line numbers for all modules. (The
/LINE parameter can generate a large amount of
output.)

4. By just pressing Enter in response to the libraries
prompt, an automatic library search is performed.

9-23

Once LINK locates all libraries, the linker map
displays a list of segments in the relative order of their
appearance within the load module. The list looks like
this:

Start Stop Length Name Class

00000H 00028H 0029H matnoo
00030H 000F6H 00C7H
00100H 00100H 0000H
00100H 038D3H 37D4H
038D4H 04921H 104EH

074A0H 074A0H 0000H
074A0H 074A0H 0000H
074A0H 0759FH 0100H
075A0H 07925H 0386H
07930H 082A9H 097AH

mat win

CODE

ENTXQQ

CODE

INIXQQ

CODE

FILVQQ

CODE

FILUQQ_

_C0DE

CODE

HEAP

MEMORY

STACK

DATA

CONST

The information in the Start and Stop columns shows
a 20-bit hex address of each segment relative to
location zero. Location zero is the beginning of the
load module. The addresses displayed are not the
absolute addresses of where these segments are
loaded. To find the absolute address of a segment,
you must determine where the segment listed as being
at relative zero is actually loaded; then add the
absolute address to the relative address shown in the
linker map. The procedure used to determine where
relative zero is actually located is discussed in this
chapter, in the section called "How to Determine the
Absolute Address of a Segment."

9-24

Because you specified the /MAP parameter, the
public symbols are displayed by name and by value.
For example:

Address

Publ ics

Name

0492:0003H

ABSNQQ

06CD:029FH

ABSRQQ

0492:00A3H

ADDNQQ

06CD:0087H

ADDRQQ

0602:000FH

ALLHQQ

0010:1BCEH

WT4VQQ

0010

1D7EH

WTFVQQ

0010

1887H

WTIVQQ

0010

19E2H

WTNVQQ

0010

11B2H

WTRVQQ

Address

Publics

Value

0000:0001H

MAIN

0000

0010H

ENTGQQ

0000

0010H

MAINQQ

0003

0000H

BEGXQQ

0003

0095H

ENDXQQ

F82B.-F31CH

CRCXQQ

F82B:F31EH

CRDXQQ

F82B:F322H

CESXQQ

F82B:F5B8H

FNSUQQ

F82B

F5E0H

OUTUQQ

9-25

The addresses of the public symbols are in the
segment. -off set format, showing the location relative to
zero as the beginning of the load module. In some
cases, an entry may look like this:

F8CC-.EBE2H

This entry appears to be the address of a load module
that is almost 1 megabyte in size. Actually, the area
being referenced is relative to a segment base that is
pointing to a segment below the relative zero
beginning of the load module. This condition
produces a pointer that has effectively gone negative.
The memory map that follows illustrates this point.

When LINK has completed, the following message is
displayed:

Program entry point at 0003:0000

How to Determine the Absolute Address of a
Segment

The linker map displays a list of segments in the
relative order of their appearance within the load
module. The information displayed shows a 20-bit
hex address of each segment relative to location zero.
The addresses displayed are not the absolute addresses
where these segments are located. To determine
where relative zero is actually located, you must use
DEBUG. DEBUG is described in detail in Chapter 12
of the DOS Technical Reference.

Using DEBUG,

1 . Load the application. Note the segment value in
CS and the offset within that segment to the entry
point as shown in IP. The last line of the linker

9-26

map also describes this entry point, but uses
relative values, not the absolute values shown by
CS and IP.

2. Subtract the relative entry as shown at the end of
the map listing from the CS:IP value. For
example, let's say CS is at 05DC and IP is at zero.

The linker map shows the entry point at
0100:0000. (0100 is a segment ID or paragraph
number; 0000 is the offset into that segment.)

In this example, relative zero is located at
04DC:0000, which is 04DC0 absolute.

If a program is loaded low, the relative zero location is
located at the end of the Program Segment Prefix, in
the location DS plus 100H.

Messages

All messages, except for the warning messages, cause
the LINK session to end. Therefore, after you locate
and correct a problem, you must rerun LINK.

Messages appear both in the list file and on the display
unless you direct the list file to CON, in which case
the display messages are suppressed.

All of the linker messages are included in Appendix A.

9-27

Notes:

9-28

Chapter 10. DEBUG Program

Contents

Introduction 10-3

How to Start the DEBUG Program 10-4

The DEBUG Command Parameters 10-6

The DEBUG Commands 10-13

Information Common to All DEBUG

Commands 10-13

A (Assemble) Command 10-15

C (Compare) Command 10-19

D (Dump) Command 10-20

E (Enter) Command 10-23

F (Fill) Command 10-26

G (Go) Command 10-27

H (Hexarithmetic) Command 10-30

I (Input) Command 10-31

L (Load) Command 10-32

M (Move) Command 10-35

N (Name) Command 10-36

O (Output) Command 10-38

P (Proceed) Command 10-39

10-1

Q (Quit) Command 10-40

R (Register) Command 10-41

S (Search) Command 10-46

T (Trace) Command 10-47

U (Unassemble) Command 10-49

W (Write) Command 10-52

10-2

Introduction

This chapter explains how to use the DEBUG
program.

The DEBUG program can be used to:

• Provide a controlled testing environment so you
can monitor and control the execution of a
program to be debugged. You can fix problems in
your program directly, and then execute the
program immediately to determine if the problems
have been resolved. You do not need to
reassemble a program to find out if your changes
worked.

• Load, alter, or display any file.

• Execute object files. Object files are executable
programs in machine language format.

10-3

How to Start the DEBUG Program

To start DEBUG, type:

DEBUG [d:][path][filename[.ext]][parml][parm2]

If you enter filename, the DEBUG program loads the
specified file into memory. You may now type
commands to alter, display, or execute the contents of
the specified file.

If you do not enter a filename, you must either work
with the present memory contents, or load the
required file into memory by using the Name and Load
commands. Then you can type commands to alter,
display, or execute the memory contents.

The optional parameters, parm 1 and parm2 , represent
the optional parameters for the named filespec. For
example,

DEBUG DISKC0MP.COM A: B:

In this command, the A: and B: are the parameters
that DEBUG prepares for the DISKCOMP program.

When the DEBUG program starts, the registers and
flags are set to the following values for the program
being debugged:

• The segment registers (CS, DS, ES, and SS) are
set to the bottom of free memory; that is, the first
segment after the end of the DEBUG program.

• The Instruction Pointer (IP) is set to hex 0100.

• The Stack Pointer (SP) is set to the end of the
segment, or the bottom of the transient portion of
the program loader, whichever is lower. The
segment size at offset 6 is reduced by hex 100 to
allow for a stack that size.

10-4

• The remaining registers (AX, BX, CX, DX, BP,
SI, and DI) are set to zero. However, if you start
the DEBUG program with a filespec, the CX
register contains the length of the file in bytes. If
the file is greater than 64K, the length is
contained in registers BX and CX (the high
portion in BX).

• The initial state of the flags is:

NV UP EI PL NZ NA PO NC

• The default disk transfer address is set to hex 80
in the code segment.

All of available memory is allocated; therefore, any
attempt by the loaded program to allocate memory
fails.

Notes:

1 . If a file loaded by DEBUG has an extension of
.EXE, DEBUG does the necessary relocation and
sets the segment registers, stack pointer, and
Instruction Pointer to the values defined in the
file. The DS and ES registers, however, point to
the Program Segment Prefix at the lowest
available segment. The BX and CX registers
contain the size of the program (smaller than the
file size).

The program is loaded at the high end of memory
if the appropriate parameter was specified when
the linker created the file. Refer to ".EXE File
Structure and Loading" in Chapter 9 of the DOS
Technical Reference manual for more information
about loading .EXE files.

2. If a file loaded by DEBUG has an extension of
.HEX, the file is assumed to be in INTEL hex
format, and is converted to executable form while
being loaded.

10-5

The DEBUG Command Parameters

Parameter

Definition

address

Enter a one- or two-part designation in
one of the following formats:

• An alphabetic segment register
designation, plus an offset value,
such as:

CS:0100

• A segment address, plus an offset
value, such as:

4BA:0100

• An offset value only, such as:

100

(In this case, each command uses a
default segment.)

Note:

1 . In the first two formats, the colon
is required to separate the values.

10-6

Parameter

address

Definition

All numeric values are
hexadecimal and may be entered
as 1-4 characters.

The memory locations specified
in address must be valid; that is,
they must actually exist.
Unpredictable results occur if an
attempt is made to access a
nonexistent memory location.

byte

Enter a 1 or 2 character hexadecimal
value.

drive

Enter 1 or 2 digits (for example, for
drive A or 1 for drive B) to indicate
which drive data is to be loaded from or
written to.

(Refer to the Load and Write
commands.)

filespec

Enter a one- to three-part file
specification consisting of a drive
designation, filename, and filename
extension. All three fields are optional.
However, for the Name command to be
meaningful, you should at least specify a
drive designator or a filename.

(Refer to the Name command.)

list

Enter 1 or more byte and/or string
values. For example,

F3 ' XYZ ' 8D 4 "abed:"

has five items in the list (that is, three
byte entries and two string entries
having a total of 10 bytes).

10-7

Parameter

Definition

portaddress

Enter a 1-4 character hexadecimal value
to specify an 8- or 16-bit port address.

(Refer to the Input and Output
commands.)

range

Enter either of the following formats to
specify the lower and upper addresses of
a range:

• address address

For example:

CS:100 110

Note: Only an offset value is
allowed in the second address. The
addresses must be separated by a
space or comma.

10-8

Parameter

Definition

range

• address L value

where value is the number of bytes
in hexadecimal to be processed by
the command. For example:

CS:100L 11
Notes:

1. The limit for range is hex 10000, so
the sum of value and the offset part
of address cannot exceed 64K bytes.
To specify a value of 64K bytes
within four hexadecimal characters,
enter 0000 (or 0).

2. The memory locations specified in
range must be valid; that is, they
must actually exist. Unpredictable
results will occur if an attempt is
made to access a non-existent
memory location.

registername

Refer to the Register command.

10-9

Parameter

Definition

sector sector

Enter 1-3 character hexadecimal values
to specify:

1 . The starting relative sector number

2. The number of sector numbers to
be loaded or written

In DEBUG, relative sectors are obtained
by counting the sectors on the disk
surface. The sector at track 0, sector 1,
head (the first sector on the disk) is
relative sector 0. The numbering
continues for each sector on that track
and head, then continues with the first
sector on the next head of the same
track. When all sectors on all heads of
the track have been counted, numbering
continues with the first sector on head
of the next track.

Note: This is a change from the
sector mapping used by DOS
Version 1.10.

The maximum number of sectors that
can be loaded or written with a single
command is hex 80. A sector contains
512 bytes.

(Refer to the Load and Write
commands.)

10-10

Parameter

string

Definition

Enter characters enclosed in quotation
marks. The quotation marks can be
either single (') or double (" ").

The ASCII values of the characters in
the string are used as a list of byte
values.

Within a string, the opposite set of
quotation marks can be used freely as
characters. However, if the same set of
quotation marks (as the delimiters) must
be used within the string, then the
quotation marks must be doubled. The
doubling does not appear in memory.
For example:

1. 'This "literal" is correct'

2. 'This ' 'literal' ' is correct'

3. 'This 'literal' is not correct'

4. 'This '"literal"' is not correct'

5. "This 'literal' is correct"

6. "This '"literal"' is correct"

7. "This 'literal' is not correct"

8. "This ' 'literal' ' is not correct"

In the second and sixth cases above, the
word literal is enclosed in one set of
quotation marks in memory. In the
fourth and eighth cases above, the word
literal is not correct unless you really
want it enclosed in two sets of quotation
marks in memory.

10-11

Parameter

Definition

value

Enter a 1-4 character hexadecimal value
to specify:

• The numbers to be added and
subtracted (refer to the
Hexarithmetic command), or

• The number of instructions to be
executed by the Trace command, or

• The number of bytes a command
should operate on. (Refer to the
Trace, Proceed, and Hexarithmetic
commands.)

10-12

The DEBUG Commands

This section presents a detailed description of how to
use the commands to the DEBUG program. The
commands appear in alphabetic order; each with its
format and purpose. Examples are provided where
appropriate.

Information Common to All DEBUG
Commands

The following information applies to the DEBUG
commands:

• A command is a single letter, usually followed by
one or more parameters.

• Commands and parameters can be entered in
uppercase or lowercase, or a combination of both.

• Commands and parameters may be separated by
delimiters. Delimiters are only required, however,
between two consecutive hexadecimal values.
Thus, these commands are equivalent:

dcs:100 110
d cs:100 110
d,cs:100,110

• Press Ctrl-Break to end commands.

• Commands become effective only after you press
the Enter key.

• For commands producing a large amount of
output, you can press Ctrl-NumLock to suspend
the display to read it before it scrolls away. Press
any other character to restart the display.

10-13

You can use the control keys and the DOS editing
keys, described in Chapter 3 of DOS User's Guide
while using the DEBUG program.

If a syntax error is encountered, the line is
displayed with the error pointed out as follows:

d cs:100 CS: 110

Aerror

In this case, the Dump command is expecting the
second address to contain only a hexadecimal
offset value. It finds the S, which is not a valid
hexadecimal character.

The prompt from the DEBUG program is a
hyphen (-).

The DEBUG program resides on your DOS
Supplemental Program diskette.

10-14

A (Assemble)
Command

Purpose: To assemble IBM Personal Computer Macro
Assembler language statements directly into
memory.

Format: A[address]

Remarks: All numeric input to the Assemble command is in

hexadecimal. The assembly statements you enter are
assembled into memory at successive locations,
starting with the address specified in address. If no
address is specified, the statements are assembled
into the area at CS:0100, if no previous Assemble
command was used, or into the location following
the last instruction assembled by a previous
Assemble command. When all desired statements
have been entered, press Enter when you are
prompted for the next statement, to return to the
DEBUG prompt.

DEBUG responds to invalid statements by
displaying:

Aerror

and redisplaying the current assemble address.

DEBUG supports standard 8086/8088 assembly
language syntax (and the 8087 instruction set), with
the following rules:

• All numeric values entered are hexadecimal and
can be entered as 1-4 characters.

• Prefix mnemonics must be entered in front of
the opcode to which they refer. They can also be
entered on a separate line.

10-15

A (Assemble)
Command

The segment override mnemonics are CS:, DS:,
ES:,andSS:.

String manipulation mnemonics must explictly
state the string size. For example, MOVSW
must be used to move word strings and MOVSB
must be used to move byte strings.

The mnemonic for the far return is RETF.

The assembler will automatically assemble
short, near, or far jumps and calls depending on
byte displacement to the destination address.
These can be overridden with the NEAR OR
FAR prefix. For example:

0100
0100

0100

0500 JMP 502
0502 JMP NEAR 505
0505 JMP FAR 50A

;a 2 byte short jump
;a 3 byte near jump
;a 5 byte far jump

The NEAR prefix can be abbreviated to NE,
but the FAR prefix cannot be abbreviated.

DEBUG cannot tell whether some operands
refer to a word memory location or a byte
memory location. In this case, the data type
must be explicity stated with the prefix WORD
PTR or BYTE PTR. DEBUG will also accept
the abbreviations WO and BY. For example:

NEG
DEC

BYTE PTR
WO [SI]

[128]

DEBUG also cannot tell whether an operand
refers to a memory location or to an immediate
operand. DEBUG uses the common convention
that operands enclosed in square brackets refer
to memory. For example:

10-16

A (Assemble)
Command

MOV AX, 21 ;Load AX with 21H
MOV AX, [21] ;Load AX with the

contents of

memory location

21H

Two popular pseudo-instructions have also
been included. The DB opcode assembles byte
values directly into memory. The DW opcode
assembles word values directly into memory.
For example:

DB 1,2, 3, 4, "THIS IS AN EXAMPLE"
DB "THIS IS A QUOTE: "'
DB "THIS IS A QUOTE: '"

DW 1000,2000,3000:", BACH:"

All forms of the register indirect commands are
supported. For example:

ADD

BX,34[BP+2],

.[SI-

■1]

POP

[BP+DI]

PUSH

[SI]

All opcode synonyms are

: SU

pported.

For

example:

LOOPZ

100

LOOPE

100

200

JNBE

200

10-17

A (Assemble)
Command

For 8087 opcodes the WAIT or FWAIT prefix
must be explictly specified. For example:

FWAIT FADD ST,ST(3) ;This line will assemble

a FWAIT prefix
FLD TBYTE PTR [BX] ;This line will not

Example:

Odebug
-a200

08B4
08B4
08B4
08B4

0200 xor ax, ax
0202 mov [bx],ax
0204 ret
0205

10-18

C (Compare)
Command

Purpose: Compares the contents of two blocks of memory.

Format: C range address

Remarks: The contents of the two blocks of memory are
compared; the length of the comparison is
determined from the range. If unequal bytes are
found, their addresses and contents are displayed, in
the form:

addrl bytel byte2 addr2

where, the first half (addrl bytel) refers to the
location and contents of the mismatching locations in
range, and the second half (byte2 addr2) refers to
the byte found in address.

If you enter only an offset for the beginning address
of range, the C command assumes the segment
contained in the DS register. To specify an ending
address for range, enter it with only an offset value.

Example: C 100L20 200

The 32 bytes (hex 20) of memory beginning at
DS:100 are compared with the 32 bytes beginning at
DS:200. L20 is the range.

10-19

D (Dump)
Command

Purpose: Displays the contents of a portion of memory.

Format:

D [address]

or
D [range]
Remarks: The dump is displayed in two parts:

1 . A hexadecimal portion. Each byte is displayed
in hexadecimal.

2. An ASCII portion. The bytes are displayed as
ASCII characters. Unprintable characters are
indicated by a period (.).

With a 40-column system display format, each line
begins on an 8-byte boundary and shows 8 bytes.

With an 80-column system display format, each line
begins on a 16-byte boundary and shows 16 bytes.
There is a hyphen between the 8th and 9th bytes.

Note: The first line may have fewer than 8 or
1 6 bytes if the starting address of the dump is
not on a boundary. In this case, the second line
of the dump begins on a boundary.

10-20

D (Dump)
Command

The Dump command has two format options:

Option 1

Use this option to display the contents of hex 40
bytes (40-column mode) or hex 80 bytes (80-column
mode). For example:

D address

or
D

The contents are dumped starting with the specified
address.

If you do not specify an address, the D command
assumes the starting address is the location following
the last location displayed by a previous D command.
Thus, it is possible to dump consecutive 40-byte or
80-byte areas by entering consecutive D commands
without parameters.

If no previous D command was entered, the location
is offset hex 100 into the segment originally
initialized in the segment registers by DEBUG.

Note: If you enter only an offset for the starting
address, the D command assumes the segment
contained in the DS register.

10-21

D (Dump)
Command

Option 2

Use this option to display the contents of the
specified address range. For example:

D range

Note: If you enter only an offset for the
starting address, the D command assumes the
segment contained in the DS register. If you
specify an ending address, enter it with only an
offset value.

For example:

D cs:100 IOC

A 40-column display format might look like this:

04BA:0100 42 45 52 54 41 20 54 00
BERTA T.

04BA:0108 20 42 4F 52 47

BORG

10-22

E (Enter)
Command

Purpose: The Enter command has two modes of operation:

• Replaces the contents of one or more bytes,
starting at the specified address, with the values
contained in the list. (See Option 1.)

• Displays and allows modification of bytes in a
sequential manner. (See Option 2.)

Format: E address [list]

Remarks: If you enter only an offset for the address, the E

command assumes the segment contained in the DS
register.

The Enter command has two format options:

Option 1

Use this option to place the list in memory beginning
at the specified address.

E address list
For example:

E ds:100 F3 "xyz" 8D

Memory locations ds:100 through ds:104 are filled
with the 5 bytes specified in the list.

Option 2

Use this option to display the address and the byte of
a location, then the system waits for your input.

10-23

E (Enter)
Command

For example:

E address

Enter a 1- or 2-character hexadecimal value to
replace the contents of the byte; then take any of the
next three actions:

1 . Press the space bar to advance to the next
address. Its contents are displayed. If you want
to change the contents take action 1 , above.

To advance to the next byte without changing
the current byte, press the space bar again.

2. Enter a hyphen (-) to back up to the preceding
address. A new line is displayed with the
preceding address and its contents. If you want
to change the contents take option 1, above.

To back up one more byte without changing the
current byte, enter another hyphen.

3. Press the Enter key to end the Enter command.

Note: Display lines can have 4 or 8 bytes of
data, depending on whether the system display
format is 40- or 80-column. Spacing beyond an
8-byte boundary causes a new display line, with
the beginning address, to be started.

10-24

E (Enter)
Command

For example:

E cs:100

might cause this display:

04BA:0100 EB._

To change the contents of 04BA:0100 from hex EB
to hex 41, enter 41.

04BA:0100 EB.41_

To see the contents of the next three locations,
press the space bar three times. The screen might
look like this:

04BA:0100 EB.41 10. 00. BC._

To change the contents of the current location
(04BA:0103) from hex BC to hex 42, enter 42.

04BA:0100 EB.41 10. 00. BC.42_

Now, suppose you want to back up and change the
hex 10 to hex 6F. This is what the screen would look
like after entering two hyphens and the replacement
byte:

04BA
04BA
04BA

0100 EB.41 10.00. BC.42-
0102 00.-

0101 10. 6F

Press the Enter key to end the Enter command.
You will see the hyphen (-) prompt.

10-25

F (Fill)
Command

Purpose: Fills the memory locations in the range with the
values in the list.

Format: F range list

Remarks: If the list contains fewer bytes than the address
range, the list is used repeatedly until all the
designated memory locations are filled.

If the list contains more bytes than the address
range, the extra list items are ignored.

Note: If you enter only an offset for the starting
address of the range, the Fill command assumes
the segment contained in the DS register.

Example: F 4BA: 100 L 5 F3 "XYZ" 8D

Memory locations 04BA:100 through 04BA:104 are
filled with the 5 bytes specified. Remember that the
ASCII values of the list characters are stored. Thus,
locations 100-104 will contain F3 58 59 5 A 8D.

10-26

G(Go)
Command

Purpose: Executes the program you are debugging.

Stops the execution when the instruction at a
specified address is reached (breakpoint), and
displays the registers, flags, and the next instruction
to be executed.

Format: G [=address] [address [address...]]

Remarks: Program execution begins with the current

instruction, whose address is determined by the
contents of the CS and IP registers, unless
overridden by the =address parameter (the = must
be entered). If =address is specified, program
execution begins with CS:=address.

The Go command has two format options:

Option 1

Use this option to execute the program you are
debugging without breakpoints. For example:

G [=address]

This option is useful when testing program
execution with different parameters each time.
(Refer to the Name command.) Be certain the
CS:IP values are set properly before issuing the G
command, if not using =address.

10-27

G(Go)
Command

Option 2

This option performs the same function as Option 1
but, in addition, allows breakpoints to be set at the
specified addresses. For example:

G [=address] address
[address . . . ]

This method causes execution to stop at a specified
location so the system/program environment can be
examined.

You can specify up to ten breakpoints in any order.
You may wish to take advantage of this if your
program has many paths, and you want to stop the
execution no matter which path the program takes.

The DEBUG program replaces the instruction codes
at the breakpoint addresses with an interrupt code
(hex CC). If any one breakpoint is reached during
execution, the execution is stopped, the registers and
flags are displayed, and all the breakpoint addresses
are restored to their original instruction codes. If no
breakpoint is reached, the instructions are not
restored.

Notes:

1 . Once a program has reached completion
(DEBUG has displayed the "Program
terminated normally" message), it is necessary
to reload the program before it can be executed
again.

2. Make sure that the address parameters refer to
locations that contain valid 8088 instruction

10-28

G(Go)
Command

codes. If you specify an address that does not
contain the first byte valid instruction,
unpredictable results occur.

3. The stack pointer must be valid and have 6
bytes available for the Go command; otherwise,
unpredictable results occur.

4. If only an offset is entered for a breakpoint, the
G command assumes the segment contained in
the CS register.

5. Do not set breakpoints at instructions in
read-only memory (ROM BIOS or ROM
BASIC).

For example:

G 102 1EF 208

Execution begins with the current instruction,
whose address is the current values of CS:IP. The
= address parameter was not used.

Three breakpoints are specified; assume that the
second is reached. Execution stops before the
instruction at location CS:1EF is executed, the
original instruction codes are restored, all three
breakpoints are removed, the display occurs, and the
Go command ends.

Refer to the Register command for a description of
the display.

10-29

H (Hexarithmetic)
Command

Purpose: Adds the two hexadecimal values, then subtracts the
second from the first.

Displays the sum and difference on one line.
H value value

Format:
Example:

H0F8

17 07

The hexadecimal sum of 000F and 0008 is 0017, and
their difference is 0007.

10-30

I (Input)
Command

Purpose: Inputs and displays (in hexadecimal) 1 byte from the
specified port.

Format: I port address

Example: I 2F8

The single hexadecimal byte read from port 02F8 is
displayed (6B).

10-31

L (Load)
Command

Purpose: Loads a file or absolute disk sectors into memory.

Format: L [address [ drive sector sector]]

Remarks: The maximum number of sectors that can be loaded
with a single Load command is hex 80.

Note: DEBUG displays a message if a disk read
error occurs. You can retry the read operation
by pressing F3 to re-display the Load command.
Then, press the Enter key.

The Load command has two format options:

Option 1

Use this option to load data from the disk specified
by drive, and place the data in memory beginning at
the specified address. For example:

L address drive sector sector

The data is read from the specified starting relative
sector (first sector) and continues until the requested
number of sectors is read (second sector).

Note: If you only enter an offset for the
beginning address, the L command assumes the
segment contained in the CS register.

For example, to load data, you might enter:

L DS: 100 1 0F 6D

10-32

L (Load)
Command

The data is loaded from the diskette in drive B and
placed in memory beginning at DS:100. 6DH (109)
consecutive sectors of data are transferred, starting
with relative sector hex OF (15) (the 16th sector on
the diskette).

Note: Option 1 cannot be used if the drive
specified is a network drive.

Option 2

When issued without parameters, or with only the
address parameter, use this option to load the file
whose filespec is at CS:80. For example:

L address

This condition is met by specifying the filespec
when starting the DEBUG program, or by using the
Name command.

Note: If DEBUG was started with a filespec
and subsequent Name commands were used,
you may need to enter a new Name command
for the proper filespec before issuing the Load
command.

The file is loaded into memory beginning at CS:100
(or the location specified by address), and is read
from the drive specified in the filespec (or from the
default drive, if none was specified). Note that files
with extensions of .COM or .EXE are always loaded
at CS:100-if you specified an address, it is ignored.

10-33

L (Load)
Command

The BX and CX registers are set to the number of
bytes read; however, if the file being loaded has an
extension of .EXE, BX and CX are set to the actual
program size. The file may be loaded at the high end
of memory. Refer to the notes in "How to Start the
DEBUG Program" at the beginning of this chapter
for the conditions that are in effect when .EXE or
.HEX files are loaded.

For example:

DEBUG

-N myprog

-L

The file named myprog is loaded from the default
diskette and placed in memory beginning at location
CS:0100.

10-34

Purpose:

M (Move)
Command

Moves the contents of the memory locations
specified by range to the locations beginning at the
address specified.

Format: M range address

Remarks:

Example:

Overlapping moves are always performed without
loss of data during the transfer. (The source and
destination areas share some of the same memory
locations.)

The data in the source area remains unchanged
unless overwritten by the move.

Notes:

1 . If you enter only an offset for the beginning
address of the range, the M command assumes
the segment contained in the DS register. If you
specify an ending address for the range, enter it
with only an offset value.

2. If you enter only an offset for the address of the
destination area, the M command assumes the
segment contained in the DS register.

M CS:100 110 500

The 17 bytes of data from CS: 100 through CS:110
are moved to the area of memory beginning at
DS:500.

10-35

N (Name)
Command

Purpose: The Name command has two functions:

• Formats file control blocks for the first two
filespecs, at CS:5C and CS:6C. (Starting
DEBUG with a filespec also formats a file
control block at CS:5C.)

The file control blocks are set up for the use of
the Load and Write commands, and to supply
required filenames for the program being
debugged.

• All specified filespecs and other parameters are
placed exactly as entered, including delimiters,
in a parameter save area at CS:81, with CS:80
containing the number of characters entered.
Register AX is set to indicate the validity of the
drive specifiers entered with the first two
filespecs.

Format: N [d:][path]filename[.ext]

Remarks: If you start the DEBUG program without a filespec,
you must use the Name command before a file can
be loaded with the L command.

10-36

Example:

N (Name)
Command

DEBUG

-N myprog
-L

To define filespecs or other parameters required by
the program being debugged, enter:

DEBUG myprog
-N filel file2

In this example, DEBUG loads the file myprog at
CS:100, and leaves the file control block at CS:5C
formatted with the same filespec. Then, the Name
command formats file control blocks for filel and
filel at CS:5C and CS:6C, respectively. The file
control block for myprog is overwritten. The
parameter area at CS:81 contains all characters
entered after the N, including all delimiters, and
CS:80 contains the count of those characters (hex
OC).

10-37

O (Output)
Command

Purpose: Sends the byte to the specified output port.
Format: O portaddress byte

Example: To send the byte value 4F to output port 2F8, enter:
2F8 4F

10-38

P (Proceed)
Command

Purpose: Causes the execution of a subroutine call, a loop
instruction, an interrupt, or a repeat string
instruction to stop at the next instruction.

Format: P[= address] [value]

Remarks: When at a subroutine call, a loop instruction, an
interrupt, or a repeat string instruction, issue the
Proceed command to execute the instruction (as an
atomic operation), and return control at the next
instruction. The Proceed command has the same
syntax as the Trace command. Specifing PO, is the
same as specifying TO.

Example: If the following instructions are executed:

0100 CALL 10000103 JC

XOR AX, AX

1XXX RET

And CS:IP was pointing to the CALL 1000
instruction, typing P causes the execution of the
subroutine and returns control to DEBUG at the JC
instruction.

10-39

Q (Quit)

Command

Purpose: Ends the DEBUG program.

Format: Q

Remarks: The file that you are working on in memory is not
saved by the Quit command. You must use the
Write command to save the file.

DEBUG returns to the command processor which
then issues the normal command prompt.

Example:

-O
A>

10-40

R (Register)
Command

Purpose: The Register command has three functions:

• It displays the hexadecimal contents of a single
register, with the option of changing those
contents.

• It displays the hexadecimal contents of all the
registers, plus the alphabetic flag settings, and
the next instruction to be executed.

• It displays the eight 2-letter alphabetic flag
settings, with the option of changing any or all
of them.

Format: R [registername]

Remarks: When the DEBUG program starts, the registers and
flags are set to certain values for the program being
debugged. (Refer to "How to Start the DEBUG
Program" at the beginning of this chapter.)

Display a

Single Register

The valid

registernames are

Both IP and PC refer to the instruction pointer.

10-41

R (Register)
Command

For example, to display the contents of a single
register, you might enter:

R AX

The system might respond with:

AX F1E4

Now you may take one of two actions:

• Press Enter to leave the contents unchanged,
or

• Change the contents of the AX register by
entering a 1-4 character hexadecimal value, such
as hex FFF.

AX F1E4
:FFF_

Now pressing Enter changes the contents of the AX
register to hex OFFF.

Display All Registers and Flags

To display the contents of all registers and flags (and
the next instruction to be executed), type:

The system might respond with:

AX=0E00 BX=00FF CX=0007 DX=01FF

SP=039D BP=0000 SI=005C DI=0000

DS=04BA ES=04BA SS=04BA CS=04BA

IP=011A NV UP DI NG NZ AC PE NC

04BA:011A CD21 INT 21

10-42

R (Register)
Command

The first four lines display the hexadecimal contents
of the registers and the eight alphabetic flag settings.
The last line indicates the location of the next
instruction to be executed, and its hexadecimal and
unassembled formats. This is the instruction pointed
to by CS:IP.

Note: A system with an 80-column display
shows:

1 st line - 8 registers

2nd line - 5 registers and 8 flag settings

3rd line - next instruction information

A system with a 40-column display shows:

1st line - 4 registers

2nd line - 4 registers

3rd line - 4 registers

4th line - 1 register and 8 flag settings

5th line - next instruction information

Display All Flags

There are eight flags, each with 2-letter codes to
indicate either a set condition or a clear condition.

The flags appear in displays in the same order as
presented in the following table:

10-43

R (Register)
Command

Flag Name

Set

Clear

Overflow (yes/no)

Direction (decrement/increment)

Interrupt (enable/disable)

Sign (negative/positive)

Zero (yes/no)

Auxiliary carry (yes/no)

Parity (even/odd)

Carry (yes/no)

Figure 10-1 Alphabetic Flag Settings

To display all flags, enter:

R F

If all the flags are in a set condition, the response is:

OV DN EI NG ZR AC PE CY -_

Now you can take one of two actions:

1 . Press Enter to leave the settings unchanged.

2. Change any or all of the settings.

10-44

R (Register)
Command

To change a flag, just enter its opposite code. The
opposite codes can be entered in any order — with or
without intervening spaces. For example, to change
the first, third, fifth, and seventh flags, enter:

OV DN EI NG ZR AC PE CY - PONZDINV

They are entered in reverse order in this example.

Press Enter and the flags are modified as specified,
the prompt appears, and you can enter the next
command.

If you want to see if the new codes are in effect,
enter:

R F

The response is:

NV DN DI NG NZ AC PO CY -_

The first, third, fifth, and seventh flags are changed
as requested. The second, fourth, sixth, and eighth
flags are unchanged.

Note: A single flag can be changed only once
per R F command.

10-45

S (Search)
Command

Purpose: Searches the range for the character(s) in the list.

Format: S range list

Remarks: All matches are indicated by displaying the addresses
where matches are found.

A display of the prompt (-) without an address
means that no match was found.

Note: If you enter only an offset for the starting
address of the range, the S command assumes
the segment contained in the DS register.

Example: If you want to search the range of addresses from
CS: 100 through CS: 1 10 for hex 41 , type:

S CS:100 110 41

If two matches are found the response might be:

04BA:0104
04BA:010D

If you want to search the same range of addresses as
in the previous example for a match with the
4-byte-long list, enter:

S CS:100 L 11 41 "AB" E

The starting addresses of all matches are listed. If
no match is found, no address is displayed.

10-46

T (Trace)
Command

Purpose: Executes one or more instructions starting with the
instruction at CS;IP, or at =address if it is specified.
The = must be entered. One instruction is assumed,
but you can specify more than one with value.
Displays the contents of all registers and flags after
each instruction executes. For a description of the
display format, refer to the Register command.

Format: T [=address][value]

Remarks: The display caused by the Trace command continues
until value instructions are executed. Therefore,
when tracing multiple instructions, remember you
can suspend the scrolling at any time by pressing
Ctrl-NumLock. Resume scrolling by entering any
other character.

Notes:

1 . The Trace command disables all hardware
interrupts before executing the user instruction,
and then reenables the interrupts when the trap
interrupt occurs following the execution of the
instruction.

2. TRACE should not be used with any steps that
change the contents of the 8259 interrupt mask
(ports 20 and 21).

3. If you trace an INT3 instruction, the breakpoint
is set at the INT3 location.

10-47

T (Trace)
Command

Example: T

If the IP register contains 01 1 A, and that location
contains B40E (MOV AH,0EH), this might be
displayed:

AX=0E00 BX=00FF CX=0007 DX=01FF
SP=039D BP=0000 SI=005C DI=0000
DS=04BA ES=04BA SS=04BA CS=04BA
IP=011C NV UP DI NG NZ AC PE NC
04BA:011C CD21 INT 21

This displays the results after the instruction at

01 1 A is executed, and indicates the next instruction

to be executed is the INT 21 at location 04BA:01 1C.

T 10

Sixteen instructions are executed (starting at
CS:IP). The contents of all registers and flags are
displayed after each instruction. The display stops
after the 16th instruction has been executed.
Displays may scroll off the screen unless you suspend
the display by pressing the Ctrl-NumLock keys.

10-48

U (Unassemble)
Command

Purpose:

Unassembles instructions (translates the contents of
memory into assembler-like statements) and displays
their addresses and hexadecimal values, together
with assembler-like statements. For example, a
display might look like this:

04BA
04BA
04BA

0100 206472

0103 FC

0104 7665

AND [SI+72] ,AH

CLD

JBE 016B

Format: U [address]

U [range]

Remarks: The number of bytes unassembled depends on your
system display format (whether 40 or 80 columns),
and which option you use with the Unassemble
command.

Notes:

In all cases, the number of bytes unassembled
and displayed may be slightly more than either
the amount requested or the default amount.
This happens because the instructions are of
variable lengths; therefore, to unassemble the
last instruction may include more bytes than
expected.

Make sure that the address parameters refer to
locations containing valid 8088 instruction
codes. If you specify an address that does not
contain the first byte of a valid instruction, the
display will be erroneous.

10-49

U (Unassemble)
Command

3 . If you enter only an offset for the starting
address, the U command assumes the segment
contained in the CS register.

The Unassemble command has two format options:

Option 1

Use this option to either unassemble instructions
without specifying an address, or to unassemble
instructions beginning with a specified address. For
example:

U address

Sixteen bytes are unassembled with a 40-column
display. Thirty-two bytes are unassembled while in
80-column mode.

Instructions are unassembled beginning with the
specified address.

If you do not specify an address, the U command
assumes the starting address is the location following
the last instruction unassembled by a previous U
command. Thus, it is possible to unassemble
consecutive locations, producing continuous
unassembled displays, by entering consecutive U
commands without parameters.

If no previous U command is entered, the location is
offset hex 0100 into the segment originally initialized
in the segment registers by DEBUG.

10-50

U (Unassemble)
Command

Option 2

Use this option to unassemble instructions in a
specified address range. For example:

U range

All instructions in the specified address range are
unassembled, regardless of the system display
format.

Note: If you specify an ending address, enter it
with only an offset value.

For example:

U04ba:0100 108

The display response might be:

04BA:0100 206472 AND [SI+72],AH

04BA:0103 FC CLD

04BA:0104 7665 JBE 016B

04BA:0106 207370 AND [BP+DI+70] ,DH

The same display appears if you enter:

U04BA:100 L 7

or
U 04BA:100 L 8

or
U 04BA:100 L 9

10-51

W (Write)
Command

Purpose: Writes the data being debugged to disk.

Format: W [address [drive sector sector]]

Remarks: The maximum number of sectors that can be written
with a single Write command is hex 80.

DEBUG displays a message if a disk write error
occurs. You can retry the write operation by
pressing F3 to redisplay the Write command, then
press the Enter key.

The Write command has two format options:

Option 1

Use this option to write data to disk beginning at a
specified address. For example:

W address drive sector sector

The data beginning at the specified address is
written to the disk in the indicated drive. The data is
written starting at the specified starting relative
sector (first sector) and continues until the requested
number of sectors are filled (second sector).

Notes:

1 . Be extremely careful when you write data to
absolute sectors because an erroneous sector
specification destroys whatever was on the disk
at that location.

10-52

W (Write)
Command

2. If only an offset is entered for the beginning
address, the W command assumes the segment
contained in the CS register.

3. Remember, the starting sector and the sector
count are both specified in hexadecimal.

4. Option 1 cannot be used if the drive specified is
a network drive.

For example:

W 1FD 1 100 A

The data beginning at CS:01FD is written to the
diskette in drive B, starting at relative sector hex 100
(256) and continuing for hex 0A (10) sectors.

Option 2

This option allows you to use the Write command
without specifying parameters or only specifying the
address parameter. For example:

W address

When issued as shown above, the Write command
writes the file (whose filespec is at CS:80) to disk.

This condition is met by specifying the filespec when
starting the DEBUG program, or by using the Name
command.

Note: If DEBUG was started with a filespec
and subsequent Name commands were used,

10-53

W (Write)
Command

you may need to enter a new Name command
for the proper filespec before issuing the Write
command.

In addition, the BX and CX registers must be set to
the number of bytes to be written. They may have
been set properly by the DEBUG or Load
commands, but might have been changed by a Go or
Trace command. You must be certain the BX and
CX registers contain the correct values.

The file beginning at CS:100, or at the location
specified by address, is written to the diskette in the
drive specified in filespec or the default drive if none
was specified.

The debugged file is written over the original file that
was loaded into memory, or into a new file if the
filename in the FCB didn't previously exist.

Note: An error message is issued if you try to
write a file with an extension of .EXE or .HEX.
These files must be written in a specific format
that DEBUG cannot support.

If you find it necessary to modify a file with an
extension of .EXE or .HEX, and the exact
locations to be modified are known, use the
following procedure:

10-54

W (Write)
Command

1. RENAME the file to an extension other than
.EXE or .HEX.

2. Load the file into memory using the DEBUG or
Load command.

3. Modify the file as needed in memory, but do not
try to execute it with the Go or Trace
commands. Unpredictable results would occur.

4. Write the file back using the Write command.

5. RENAME the file to its correct name.

10-55

Notes:

10-56

Appendixes

Contents

Appendix A. Messages A-3

Introduction A-3

Responses A-3

Device Error Messages A-4

Other Messages A-l 1

A-l

Notes:

A-2

Appendix A. Messages

Introduction

This appendix contains device errors (the message that DOS uses
to indicate errors while reading or writing to devices on your
system), and Other messages (the remainder of the DOS
messages) in alphabetic order. Messages are listed in bold type
and the explanation and action follow the message.

The first word of the description of each message is the name of
the program or command that generated the message.

In some cases, the message is generated by several different
programs or commands. In that case, the first word is command.
Where the message is generated by an internal DOS file, the first
word is DOS.

Responses

When any of the device error messages are displayed, the system
waits for you to respond. If you know what caused the problem,
take corrective action before choosing a response. The system
waits until you make one of these responses.

To recover from an error condition, the responses should be
made in the following order:

R Retry the operation because the error may not occur

again. The system tries the disk read or write
operation again. We strongly recommend that you use
Retry first.

A Abort the program. The system ends the program that

requested the disk read or write.

A-3

Ignore the error condition and continue the program.
(Be careful when choosing this response because data
may be lost.) If the system determines that the
condition is not dangerous, it ignores the error and
continues the program.

Device Error Messages

When an error is detected during reading or writing to any of the
devices (disk drives, printer, etc.) on your system, DOS displays
a message in the following format:

<type> error reading <device>
Abort, Retry, Ignore?

or
<type> error writing <device>
Abort, Retry, Ignore?

In these messages, <device> is the name of the device in error,
such as PRN, or B:, and <type> is one of the types listed on the
following pages:

A-4

Bad call format

Explanation: A device driver was passed an incorrect length
request header.

Action: Refer to "Responses" at the beginning of this group
of device messages.

. Use DEBUG.

• Review your programming specifications. Patch and
reassemble.

• If you are using a purchased program, contact the
dealer you purchased the device driver from.

Bad command

Explanation: A device driver has issued an invalid command
to <device>.

Action: Refer to "Responses" at the beginning of this
group of device messages.

• Review your device interface specification and DOS
driver implementation to make sure everything you are
trying to do is supported.

• Check your program to see if you have a coding
problem that needs debugging.

Bad unit

Explanation: A device driver has been passed an invalid
sub-unit number.

Action: Refer to "Responses" at the beginning of this
group of device messages. If you are using a purchased
program contact the dealer you purchased the device driver
from.

A-5

Data

Explanation: DOS was unable to read or write the data
correctly. This message usually means a disk has developed
a defective spot.

Action: Refer to "Responses" at the beginning of this
group of device messages.

FCB unavailable

Explanation: With file sharing loaded, you tried to
concurrently open more file control blocks than were
specified by the FCBS configuration command.

Action: Choose Abort as your response. Then, increase the
value of the FCBS configuration command.

General failure

Explanation: An error of a type not described elsewhere in
this list has occurred.

Action: Refer to "Responses" at the beginning of this
group of device messages. Choose Retry first. Then choose
Abort if this problem requires further investigation by a
programmer.

If you are using a purchased program, contact the dealer
you purchased it from.

Lock violation

Explanation: SHARE. The file you tried to access is locked
by someone else. This is usually a temporary situtation.

Action: Choose Retry as your first response. If the problem
still exists, choose Abort.

A-6

No paper

Explanation: The indicated printer is either out of paper or
not turned on.

Action: Turn the printer ON, press the ONLINE switch, or
add paper and retry.

Refer to "Responses" at the beginning of this group of
device messages.

Non-DOS disk

Explanation: The file allocation table contains invalid
information. The disk needs to be reformatted.

Action: Refer to "Responses" at the beginning of this
group of device messages.

Try running CHKDSK to see if any corrective action is
possible. Reformatting will correct the disk, but the files
are lost forever.

Not ready

Explanation: The named device is not ready to accept or
transmit data.

Action: Check that the disk drive door is closed and choose
Retry for your response if this is the problem.

Refer to "Responses" at the beginning of this group of
device messages.

A-7

Read fault

Explanation: DOS was unable to read the data from the
device.

Action: Refer to "Responses" at the beginning of this group
of device messages.

• Make sure the diskette is properly inserted in the drive.

• If you get the same message, choose Abort and rerun
the command with a different disk.

Sector not found

Explanation: The sector containing the data could not be
located on the disk.

Action: Refer to "Responses" at the beginning of this group
of device messages.

If you get the same message, choose Abort and rerun the
command with a different disk.

Seek

Explanation: The fixed disk or diskette drive was unable to
locate the proper track on the disk.

Action:

• Make sure the diskette is properly inserted in the drive.

• Try a different drive

. Run CHKDSK

Refer to "Responses" at the beginning of this group of
device messages.

A-8

Sharing violation

Explanation: SHARE. You tried to access a file using a
sharing mode not allowed at this time. Normally this occurs
when someone else is accessing the file in compatibility
mode for writing, or in a sharing mode that doesn't allow
you to access the file at the same time.

Action: Choose Retry as your first response. If that fails,
choose Abort.

Write fault

Explanation: DOS was unable to write the data to the
device.

Action:

• Make sure the diskette is properly inserted in the drive.

• If the diskette is not the problem, choose Retry.

• If you get the same message, choose Abort and rerun
the command with a different disk.

Refer to "Responses" at the beginning of this group of
device messages.

Write protect

Explanation: An attempt was made to write on a write
protected diskette.

Action: Investigate carefully before you decide to write on a
write protected diskette.

Important: If you attempt to use a dual-sided diskette in a
single-sided drive, or if you attempt to use a 9-sector-per-track
diskette on a version of DOS previous to version 2.00, one of the

A-9

preceding messages appears. If any of the preceding messages
appear for a diskette drive, DO NOT change diskettes before
responding with Abort, Retry, or Ignore.

A-10

Other Messages

The following messages are in alphabetic order.

Abort edit (Y/N)?

Explanation: EDLIN. This message is displayed if you
specify the /Q command to quit the edit.

Action: Type a Y to end the edit. Type a N to continue
editing the file.

About to generate .EXE file

Change diskette in drive A: and press < ENTER >

Explanation: LINK. This message appears before the .EXE
has been written if the /P switch is given.

Action: Insert diskette that the .EXE file is to be written to
into the specified drive (A: for example).

Access denied

Explanation: Commands. Executing the requrested
command violates the access mode of the file, subdirectory,
or device involved. For example, an attempt was made to
write to a file marked read-only, or read a file that is
write-only. Or an attempt was made to open a subdirectory
as a file.

Action: Use a different filename.

A-ll

All files canceled by operator

Explanation: PRINT/T. Informational message. You use
the PRINT command with the /T parameter to cancel the
printing of all queued files.

Action: This message appears on the printer.

All specified file(s) are contiguous

Explanation: CHKDSK. Informational message. The file or
files you named are all written sequentially on the disk.

Action: No action required.

Allocation error for file, size adjusted

Explanation: CHKDSK or CHKDSK/F. A filename
precedes this message. An invalid cluster number was
found in the file allocation table.

Action:

• If you specified the /F parameter, the file is truncated
at the end of the last valid cluster.

• If you did not enter the /F parameter, the message is
for your information and no action is needed. Enter:

CHKDSK/F

to correct the file size.

Amount read less than size in header

Explanation: EXE2BIN. The program portion of the file
was smaller than indicated in the file's header.

Action: Recompile or reassemble the program, and then

A-12

reLINK it.
Array element size mismatch

Explanation: LINK. A far communal array has been
declared with two or more different array element sizes (for
example, declared once as an array of characters and once
as an array of reals).

Action: Match definitions and recreate object module.

Attempt to access data outside
of segment bounds

Explanation: LINK. An object file is invalid.
Action:

• Review the .ASM file or assembled listing for
segmentation violations.

• Look for a bad reference or invalid instruction.
Attempt to put segment xxxxxx in more than one group in file

Explanation: LINK. A segment was declared to be part of
two different groups.

Action: Correct the source and recreate the object files.

Attempted write protect violation

Explanation: FORMAT. The diskette being formatted is
write protected and cannot be written on.

Action: In response to the displayed prompt, insert a new
diskette and press any key to restart formatting.

A-13

** Backing up files to target drive x**
Target Number: x

Explanation: BACKUP. Informational message telling you
the sequence of file being backed up.

Action: No action required.

Backup file sequence error

Explanation: RESTORE. A file to be restored was backed
up on more than one diskette. You did not insert the
diskette with the first part of the file.

Action: Rerun RESTORE and start with the correct
diskette.

Bad command or filename

Explanation: DOS. The command you just entered is not a
valid DOS command.

Action: Check the spelling of the command and re-enter it.

If the command name is spelled correctly, check to see that
the default drive contains the external command or batch
file you are trying to execute.

Bad internal reloc table

Explanation: LINK. Internal linker error.

Action: Record the scenario that produced this message, and
contact your IBM dealer.

A-14

Bad or missing Command Interpreter

Explanation: DOS. The disk that DOS is being started from
does not contain a copy of COMMAND.COM, or an error
occurred while the disk was being loaded.

This message also appears if COMMAND.COM has been
removed from the directory it was in originally when DOS
was started; or if the COMSPEC= parameter in the
environment points to a directory not containing
COMMAND.COM and DOS is trying to reload the
command processor.

Action: Do a System Reset. If System Reset fails to solve
the problem, start DOS with your backup DOS diskette.
Then copy COMMAND.COM from the backup diskette to
the root directory of the disk that failed.

Bad or missing < filename >

Explanation: DOS. This message appears only at startup
and indicates one of the following:

a. The name of a driver named in a DEVICE=
<filename> parameter in the CONFIG.SYS file was
not found.

b. A break address was out of bounds for the machine
size.

c. An error occurred while the driver was being loaded.
That driver is not installed by DOS.

Action:

a. For an incorrect device driver name, use the correct
spelling for the device driver name, or use the diskette
with the named device driver.

b. For items B and C, correct the coding in the device
driver.

A-15

c. If you still cannot correct the problem, see your IBM
Personal Computer dealer.

Bad Unit

Explanation: Commands. A disk I/O device driver
encountered a critical error in or within an unrecognized or
invalid device.

Action: Record the environment and sequence of events
and notify the author of the device driver or your authorized
IBM dealer.

Bad tracks found at start of partition
Partition size adjusted

Explanation: FDISK. Bad tracks were encountered in the
area of the fixed disk required by DOS. Some space was
lost at the beginning of the requested partition.

Action: No action required.

Batch file missing

Explanation: DOS. DOS could not locate the batch file it
was processing. The file may have been erased or renamed
by one of the steps within it. Batch processing stops and
the DOS prompt appears.

Action:

1 . If the filename was changed or if the file was deleted,
correct the command that changed the name(s).

2. If the file was erased, use your backup copy. If you
used EDLIN to create the file or make changes, rename
the .BAK file to .BAT. Correct the command that
deleted the file.

A-16

Explanation: DEBUG. Bad flag. An invalid flag code
setting was specified.

Action: Try the Register (R F) command again with the
correct code.

Explanation: DEBUG. Breakpoints. More than ten
breakpoints were specified for the GO command.

Action: Re-enter the GO (G) command again with ten or
fewer breakpoints.

Explanation: DEBUG. Bad register. An invalid register
name was specified.

Action: Re-enter the Register (R) command using a correct
register name.

BREAK is On|Off

Explanation: BREAK. This message indicates the status of
BREAK, either on or off.

Action: Enter the command you want. For example if
Break is off is displayed and Break is on is desired, enter the
command:

BREAK ON

A-17

Buffer size adjusted

Explanation: VDISK. VDISK found it necessary to adjust
the buffer size value in the Device = VDISK. SYS in the
CONFIG.SYS command.

Action: No action required.

Buffer size:
Sector size:
Directory entries:
Transfer size:

Explanation: VDISK. VDISK has successfully installed a
virtual disk indicating the virtual disk size, the sector size,
the number of directory entries in use, and the maximum
transfer size for the virtual disk.

Action: No action required.

Cannot CHDIR to root

Explanation: CHKDSK. CHKDSK, during its scan of the
disk, attempted to CHDIR to the root but failed. This
failed attempt is due to a damaged disk.

Action: No action required.

Cannot CHKDSK a network drive

Explanation: You cannot CHKDSK a drive that is either a
network disk or a disk that is on your computer, but is
currently being shared on the network.

Action: If the disk is being shared, you can PAUSE the
server, do CHKDSK, then CONTINUE the server.

A-18

Cannot CHKDSK a SUBSTed or ASSIGNed drive

Explanation: SUBST. SUBST hides disk/device information
necessary to CHKDSK.

Action: Remove the substitution and try again.

Cannot DISKCOMP to or from
a Network drive

Explanation: DISKCOMP. You cannot use DISKCOMP to
compare files on a network drive or on a drive that is on
your computer but is currently being shared on the network.

Action: Use COMP *.* instead of DISKCOMP. If the disk
is being shared, you can PAUSE the server, do
DISKCOMP, then CONTINUE the server.

Cannot DISKCOPY to or from
a Network drive

Explanation: DISKCOPY. You cannot use DISKCOPY to
copy files to or from a network drive or a drive that is on
your computer but is currently being shared on the network.

Action: Use COPY *.* instead of DISKCOPY. You can
also use the COPY command to copy individual files instead
of the whole diskette. Be sure your diskette is formatted. If
the disk is being shared, you can PAUSE the server, do
DISKCOPY, then CONTINUE the server.

Cannot do binary reads from a device

Explanation: COPY. You used the /B parameter with a
device name while trying to copy from the device. The copy
cannot be performed in binary mode because COPY must
be able to detect end-of-file from the device.

A-19

Action: Re-enter COPY and omit the /B parameter or use
the /A parameter after the device name.

Cannot edit .BAK file — rename file

Explanation: EDLIN. Files with the extension .BAK are
considered to be backup files, with more up-to-date
versions of the files assumed to exist. Therefore, .BAK files
shouldn't ordinarily be edited.

Action: If it is necessary to edit the .BAK file, rename the
file giving it an extension other than .BAK. Or else, copy
the file and give the copy a different filename extension.

Cannot FDISK a network drive

Explanation: FDISK. You cannot format the fixed disk
when the network is loaded.

Action: No action required.

Cannot find file object file

Change diskette and press < ENTER >

Explanation: LINK. The linker could not locate the
specified object module on the drive.

Action: Insert the correct diskette with the object file on it
and press Enter.

Warning: If it is necessary to change the diskette that
contains the open VM.TMP file, you need to exit LINK
by pressing Ctrl-Break instead of changing diskettes,
and then restart LINK with the changing drive
specified to locate the object file. Otherwise, there
may be a loss of data on the diskette inserted. This
usually occurs when using default drive value for the
object file.

A-20

Cannot find library library file
Enter new file spec:

Explanation: LINK. The specified library could not be
found on the drive.

Action: Enter the correct letter for the drive the library is
on.

Cannot find system files

Explanation: FORMAT, SYS. The hidden files
IBMBIO.COM and/or IBMDOS.COM were not found, and
the current drive is not removable.

Action: Change the current drive to one that has the system
files in the root and try again.

Cannot FORMAT a Network drive

Explanation: FORMAT. You cannot use the FORMAT
command to format a network drive or a drive on your
computer being shared on the network.

Action: If the drive is being shared, you can PAUSE the
server, do FORMAT, then CONTINUE the server.

A-21

Cannot format a SUBSTed or ASSIGNed drive

Explanation: FORMAT. The ASSIGN x=y was executed
prior to the attempted execution of FORMAT.

Action: Execute ASSIGN to restore the original drive letter
assignment. Then proceed to execute FORMAT.

Cannot JOIN to a network drive

Explanation: You cannot use the JOIN command to join a
local drive to a network drive or to join a network drive to a
local drive.

Action: No action required.

Cannot LABEL a Network drive

Explanation: You tried to create a new, or change an
existing volume label on a redirected block device.

Action: The suggested action is to retain the existing label
on that drive.

Cannot load COMMAND, system halted

Explanation: DOS. DOS attempted to reload the command
processor, but the area in which DOS keeps track of
available memory was destroyed; or the command processor
was not found in the path specified by the COMSPEC
parameter.

Action: Restart DOS. Don't forget to put the DOS diskette
in the drive.

A-22

Cannot nest response file

Explanation: LINK. You used @filespec within an
automatic response file. Automatic response files cannot be
nested.

Action:

1 . Change the initial auto response file to eliminate nested
auto response file.

2. Or, fix the syntax error if you did not intend this to be
an auto response file.

Cannot open list file

Explanation: LINK. The directory or disk is full.

Action: Insert another disk, or delete some files from the
disk that is full.

Cannot open overlay

Explanation: LINK. The directory or disk is full.

Action: Insert another disk, or delete some files from the
disk that is full.

Cannot open response file: filename

Explanation: LINK. The automatic response file could not
be found.

Action: Include drive specifier and/or path for the response
file. Place the file on the proper disk.

A-23

Cannot open run file

Explanation: LINK. The directory or disk is full.

Action: Insert another diskette, or delete some files from the
disk that is full.

Cannot open temporary file

Explanation: LINK. The directory or disk is full.

Action: Insert another disk, or delete some files from the
disk that is full.

Cannot RECOVER Entry, Processing Continued

Explanation: CHKDSK.
Action: No action required.
Cannot RECOVER to a network drive

Explanation: RECOVER. You cannot use the RECOVER
command to recover files from a network drive or from a
drive on your computer that is being shared on the network.

Action: If the drive is being shared, you can PAUSE the
server, do RECOVER, then CONTINUE the server.

Cannot reopen list file

Explanation: LINK. The original diskette was not actually
replaced.

Action: Restart the linker.

A-24

Cannot start COMMAND, exiting

Explanation: DOS. While DOS was attempting to load
another copy of the command processor, either the FILES =
parameter in the configuration file was found to contain too
small a value, or there is not enough available memory to
contain the new copy of COMMAND.COM.

Action:

Restart DOS.

• If necessary, increase the parameter value of FILES=
parameter in CONFIG.SYS.

Cannot use PRINT - use NET PRINT

Explanation: PRINT. You cannot use the PRINT command
on a network server computer. Use NET PRINT.

Action: Use NET PRINT to print the files.

CHDIR . . Failed Trying Alternate Method

Explanation: CHKDSK.
Action: Restart DOS and CHKDSK again.
Cannot SUBST to a network drive

Explanation: SUBST. You cannot use the SUBST command
to substitute a drive for a network path or substitute a
network drive for a local path.

Action: No action required.

A-25

Cannot SYS to a network drive

Explanation: SYS. You cannot use SYS to transfer system
files to a network drive or to a drive on your computer that
is currently being shared on the network.

Action: If the drive is being shared, you can PAUSE the
server, do SYS, then CONTINUE the server.

Common area longer than 65536 bytes

Explanation: LINK. User's program has more than 64K of
communal variables. Note: At the present time, only
Microsoft C programs can possibly cause this message to
appear.

Action: Rewrite your program using fewer or smaller
communal variables.

COMn: bbbb,p,d,s,t initialized

Explanation: MODE. Informational message. The
Asynchronous Communications Adapter is initialized. The
values represent:

adapter (COM1 or

bbbb

baud rate

parity

e even

o odd

n none

data bits

stop bits (1 or 2)

A-26

t type of serial device

p serial printer (serial timeouts will be retried)

- other serial device (serial timeouts will not be
retried)

Action: No action required. The feedback message from
MODE shows its interpretation of the MODE command
and the parameters you entered.

Compare error at offset XXXXXXXX

Explanation: COMP. Informational message. The files
being compared contain different values at the displayed
offset (in hexadecimal) into the file. The differing values
are also displayed in hexadecimal.

Action: No action required This message is for your
information to give you the location that contains
mismatching information in two files.

Compare process ended

Explanation: DISKCOMP. This is an informative message
indicating that DISKCOMP is finished comparing.

Action: No action required.

A-27

COM: ,e,7,l
Compare error(s) on
Track xx, side xx

Explanation: DISKCOMP. One or more locations on the
indicated track and side contain different information when
the diskettes are compared.

Action: This message is to inform you that there is a
difference between diskettes. If you want an exact copy of
a diskette, use DISKCOPY.

Compare more diskettes (Y/N)?

Explanation: DISKCOMP.

• This message indicates completion of DISKCOMP.

• You may compare more than one set of diskettes
without re-entering the DISKCOMP command.

Action: If you wish to compare another pair of diskettes,
enter Y, and DISKCOMP will ask you to insert the required
diskettes. If you do not want to compare any more
diskettes, enter N.

Compare more files (Y/N)?

Explanation: COMP. COMP has finished comparing files.
You may compare more files without re-entering the COMP
command.

Action:

If you wish to compare the contents of two more files,
enter Y, and COMP will ask you for the names of the
files to compare.

If you do not wish to compare more files, enter N.

A-28

Comparing x sectors per track, n side(s)

Explanation: DISKCOMP. The jc indicates the number of
sectors per track found on the first diskette (8 or 9). If you
use /8, then the number 8 appears. The n will be either 1 or
2, indicating the number of sides that DISKCOMP will
compare on the two diskettes. This number is determined
by the number of sides DISKCOMP was able to
successfully read from the first track of the first diskette.

Action: If x or n is not what you expected, let DISKCOMP
finish comparing diskettes. Re-enter the DISKCOMP
command with or without additional parameters.

Configuration too large

Explanation: DOS. Occurs when the number specified for
the FILES or BUFFERS commands in the CONFIG.SYS
file does not leave enough room for DOS to be loaded.

Action: Restart DOS with a different diskette, and reduce
the value specified for the FILES and/or BUFFERS
commands.

Contains xxx non-contiguous blocks

Explanation: CHKDSK. Informational message. The file
name preceding this message means that the file is not
written sequentially on the disk — it is written in xxx pieces
on different areas of the disk.

This message is for your information and does not indicate a
problem with the disk.

Action: Since fragmented files take longer to read, you
should consider copying badly fragmented files to another
disk with the COPY command. This will record the file
sequentially, resulting in better system performance when
the file is read.

A-29

Convert directory to file (Y/N)?

Explanation: CHKDSK. The directory name preceding this
message means the directory contains too much invalid
information to be usable as a directory.

Action:

• If you reply Y, CHKDSK will convert the directory to a
file so that you may examine it with DEBUG.

• If you reply N, the entry is not changed.

xxx lost clusters found in yyy chains.
Convert lost chains to files (Y/N)?

Explanation: CHKDSK. Ctrl-Break was entered during a
disk I/O operation. CHKDSK did not clean up the disk
after encountering the Ctrl-Break.

Action:

If you reply Y and you have used the /F parameter,
CHKDSK will recover each chain into a separate file.

If you reply N, CHKDSK frees the blocks up so they
can be allocated to new files.

If CHKDSK was specified (no /F), then messages
displayed afterwards are informational (no corrective
action was taken).

Copy another (Y/N)?

Explanation: DISKCOPY. This message allows you to make
exact images of additional diskettes without re-entering the
DISKCOPY command.

A-30

Action:

• If you wish to copy another entire diskette, enter Y.
DISKCOPY asks you to insert the required diskettes.

• If you do not wish to make any more copies, enter N.
Copy complete

Explanation: DISKCOPY. Informational message.

Action: No action required. The source diskette contents
have been successfully copied to the target diskette.

Copying xxx tracks

x sectors per track, n sides

Explanation: DISKCOPY. The xxx will be 40 or 80 tracks.
The jc will be 8, if the diskette was formatted using DOS
1.1; or 9, if the diskette was formatted with DOS 2.00 or
2.10; or 15 if the diskette was formatted using DOS 3.00.
The n is either 1 or 2 indicating the number of sides. If the
diskette has been formatted double sided and subsequently
formatted single sided, DISKCOPY will say it is copying 2
side(s) In this situation, use DISKCOPY /l.

If the diskette was formatted with FORMAT /8,
DISKCOPY will say Copying 9 sectors. This is due to the
fact that FORMAT will format the disk with 9 sectors, but
initializes 8. DISKCOPY mimics FORMAT in that it says,
Copying 9 sectors, but the target diskette ends up with 8
sectors per track.

Action: No action required.

A-31

Current drive is no longer valid

Explanation: COMMAND. While attempting to get the
current drive for the DOS prompt ($p), COMMAND found
that the drive is no longer valid. This can occur if your
current drive is a network drive and you delete the network
drive.

Action: Change your current drive to a valid drive.

Data record too large

Explanation: LINK. LEDATA record contains more than
1024 bytes of data.

Action: This is a translator error. Note the translator
(compiler or assembler) that produced the incorrect object
module and the circumstances under which it was produced,
and report the information to your dealer.

Delete current volume label (Y/N)?

Explanation: LABEL. You can avoid deleting the existing
label by pressing Enter rather than typing a new volume
label.

Action Type n to keep the current label.

Explanation: DEBUG. Double flag. Conflicting codes were
specified for a single flag.

Action: DEBUG is informing you that a flag can be changed
only once per Register (R F) command.

A-32

Dir path listing for volume xxxxxxx

Explanation: TREE. Informational message telling you the
volume label of the disk.

Action: No action required.

Directory entries adjusted

Explanation: VDISK. VDISK found it necessary to adjust
the number of directory entries in the
DEVICE=VDISK.SYS in the CONFIG.SYS command.

Action: No action required.

Directory is joined,

tree past this point not processed.

Explanation: CHKDSK. This is an informative message.
Joining a drive to another tree will extend the tree. The
allocation on the joined device is completely separate, and
there is no reason to CHKDSK across devices. CHKDSK is
skipping over the joined device.

Action: No action required.

Directory is totally empty, no . or ..,
tree past this point not processed.

Explanation: A subdirectory was found that did not
properly contain a . or .. entry. This usually happens when
DOS is not given a chance to update the disk properly.
During the updating process, the system may have shut
down, or you may have reloaded the system before DOS
finished the update.

Action: Try using the RECOVER command to try to
recover files on the damaged disk.

A-33

Disk boot failure

Explanation: DOS. An error occurred when you tried to
load DOS into memory.

Action: Restart the system. If subsequent attempts to start
the system also fail, place a backup DOS diskette in drive A
and restart your system.

Disk error reading drive x

Explanation: You tried to read absolute sectors on a
network drive. This cannot be done.

Action: If possible, us the Loader Write filespec option of
this DEBUG command.

Disk error writing drive x

Explanation: You tried to write to absolute sectors on a
network disk. This cannot be done.

Action: If possible, use the Loader Write filespec option of
this DEBUG command.

Disk error reading FAT X

Explanation: CHKDSK. The File Allocation Table indicated
is invalid. This can be caused by a power failure while a file
is open.

Action: If this message appears twice for FATs 1 and 2,
format the disk to make it usable again. If FORMAT fails,
the disk is probably unusable.

A-34

Disk error writing FAT X

Explanation: CHKDSK. A disk error was encountered
while CHKDSK was attempting to update the file allocation
table (FAT) on the specified drive. X will be 1 or 2,
depending on which of the 2 copies of the file allocation
table could not be written.

Action: If this message appears twice, for FAT's 1 and 2,
format the disk to make it usable again. If FORMAT fails,
discard the disk since it is probably unusable.

Disk full. Edits lost

Explanation: EDLIN. An End Edit command ended
abnormally because the disk is full (not enough free space
to save the entire file). Any editing done to the file is lost.

Action: Obtain a fresh diskette, copy the file on to the fresh
diskette, and start editing again.

Disk not compatible

Explanation: FORMAT. You cannot use the DOS
FORMAT command to format a diskette using the drive
you specified. This message informs you that the drive you
specified is not supported by the IBM device interfaces that
FORMAT requires.

Action: Obtain a compatible disk drive.

Disk unsuitable for system disk

Explanation: FORMAT. A defective track was detected
where the DOS files were to reside. The diskette can be
used only for data.

Action: The diskette can be used only for data. Use another
disk if you wish to copy DOS files.

A-35

Diskette/Drive not compatible

Explanation:. DISKCOPY, DISKCOMP. The destination
diskette /drive is different from the source diskette/drive in
a way that prohibits the copy or compare. For example, you
cannot DISKCOPY a double-sided diskette to a single-sided
diskette or DISKCOMP a 96 tpi diskette in a 48 tpi drive
with a 96 tpi diskette in a 96 tpi drive.

Action: Match the diskette/drive types and try again.

Diskettes compare OK

Explanation: DISKCOMP. Informational message. The
two diskettes just compared contain identical information.

Action: No action required.

Divide overflow

Explanation: DOS. A program tried to divide a number by
zero, or a logic error caused an internal malfunction. The
program ends and you return to DOS.

Action: Correct the programming error and continue. If this
is a purchased program, take it back to your dealer.

Do you see the leftmost 9? (Y/N)

Explanation: MODE. ,R,T was specified.

Action: Respond Y or N. This prompt is repeated until you
respond Y.

A-36

Do you see the rightmost 9? (Y/N)

Explanation: MODE. ,L,T was specified.

Action: Respond Y or N. This prompt is repeated until you
respond Y.

Do you wish to use the entire fixed
disk for DOS (Y/N) ? [ ]

Explanation: FDISK. When the "Create DOS Partition"
option is used on the current fixed disk and the fixed disk
has never been set up, this question is asked.

Action:

• If you enter Y, the entire current fixed disk is used for
DOS and it will be made active.

• If you enter N, you are asked to enter the limits of the
DOS partition you want to create.

Command format:DISKCOPY d: d: [/l]

Explanation: DISKCOPY. An invalid parameter or filename
was typed.

Action: Check the command format, and re-enter the
command.

DOS partition created

Explanation: FDISK. Informational message. A DOS
partition has been created on the fixed disk.

Action: You will need to run the FORMAT command on
the DOS partition before you can store files on the fixed
disk.

A-37

DOS partition deleted

Explanation: FDISK. Informational message. A DOS
partition no longer exists on the fixed disk.

Action: No action required.

Drive types or diskette types not compatible

Explanation: DISKCOMP or DISKCOPY. The source and
target diskettes or drives are not compatible.

Action: Refer to the DISKCOMP or DISKCOPY
commands for the allowable combinations.

Dup record too complex

Explanation: LINK. A DUP record in an assembler source
program is too deeply nested or too complicated for the
linker to expand. A single DUP requires 1024 bytes before
expansion.

Action: Reduce the number of structures or DUP statements
in the assembler source program, create a new object
module, and retry LINK.

Duplicate filename or file not found

Explanation: RENAME. You tried to rename a file to a
filename that already exists on the diskette, or the file to be
renamed could not be found on the specified (or default)
drive. RENAME is warning you that you are using the
same name for two files, or else it cannot find the file you
are trying to rename.

Action: Did you type the filename correctly? Take a second
look at the filename you want to change, and re-enter the
RENAME command.

A-38

Enter the number of the partition you
want to make active : [ 1

Explanation: FDISK. The "Change Active Partition" option
is requesting you to enter the number of the partition you
want to make active.

Action: Type the number of the partition that you want to
make active on the current fixed disk. Then press the Enter
key.

Note: The partitions are displayed above the prompt.

Enter partition size : [dddd]

Explanation: FDISK. The "Create DOS Partition" option is
requesting that you enter the size of the partition you wish
to create.

Action: The number shown in the brackets is the default
size. If you only press Enter, that size will be used as the
partition size. Otherwise, enter the desired size, then press
Enter.

Enter primary file name

Explanation: COMP. DOS asks you for primary filename.

Action: Enter the filespec of the first of two files to be
compared.

A-39

Enter 2nd file name or drive id

Explanation: COMP. DOS asks you for filespec of second of
the two files you want compared.

Action: Enter the filespec of the second of two files to be
compared, or just enter the drive letter if the filename is the
same as the primary filename.

Enter starting cylinder number..: [dddd]

Explanation: FDISK. The "Create DOS Partition" option is
requesting that you enter the starting cylinder number for
the DOS partition you are creating. The value in the
brackets is the default value. It is the starting cylinder of
the largest piece of free space on the current fixed disk.

Action: Type the starting cylinder number and press Enter,
or just press Enter to use the default value.

Entry Error

Explanation: EDLIN. EDLIN has detected a syntax error.

Action: Correct the syntax error on the last command.

Entry has a bad attribute
(or size or link)

Explanation: CHKDSK. This message may begin with one
or two periods, indicating which entry in the subdirectory
was in error. One period indicates the current directory is
in error. Two periods mean the parent directory is in error.
If you did not enter the /F parameter, no corrective action is
taken.

Action: Enter: CHKDSK /¥. CHKDSK will* then try to
correct the error.

A-40

EOF mark not found

Explanation: COMP. COMP could not find the end of valid
data in the last block of the files being compared. This
message usually occurs when comparing non-text files; it
should not occur when comparing text files.

Action: For more details, see the COMP command in
Chapter 2.

Error found, F parameter not specified
Corrections will not be written to disk

Explanation: CHKDSK. Informational message. An error
was found and you have not used the /F parameter.
CHKDSK performs its analysis as though it were going to
correct any errors detected, so that you can see the results
of its analysis, but it will not actually write the corrections
on the disk.

Action: No action required.

Error in EXE file

Explanation: DOS. An error was detected in the relocation
information placed in the file by the LINK program. This
may be due to a modification to the file.

Action:

• If you are using a purchased program, rerun the
program using your backup copy.

• If you still have trouble see your authorized dealer.

• If you are using a program you wrote yourself, go
through the LINK procedure again.

A-41

Error in EXE or HEX file

Explanation: DEBUG. The file contained invalid records or
characters.

Action: Get another copy of the program, and run DEBUG
again.

Error loading operating system

Explanation: DOS. A disk error occurred while attempting
to load your operating system from fixed disk.

Action: Restart the system. If the error persists after several
tries, restart the system, (you should start DOS from your
DOS diskette) and use the SYS command to transfer a new
copy of DOS to your fixed disk.

Error reading fixed disk

Explanation: FDISK. The FDISK program was unable to
read the startup record of the current fixed disk after five
tries.

Action: Try the FDISK program again. If after several tries
you still get the same error, consult the IBM Guide to
Operations, "Problem Determination" section. If you still
cannot solve the problem, see your IBM Personal Computer
Dealer.

Error writing fixed disk

Explanation: FDISK. The FDISK program was unable to
write the startup record of the current fixed disk after five
tries.

Action: Try the FDISK program again. If after several tries

A-42

you still get the same error, consult the IBM Guide to
Operations, "Problem Determination" section. If you still
cannot solve the problem see your IBM Personal Computer,
Dealer.

Error writing to device

Explanation: Commands. Informational message. DOS
encountered an I/O error when writing output to a device.
The device is unable to handle the number of bytes
requested.

Action: Change amount of data in the file and retry the
command.

Errors on list device indicate that
it may be off-line. Please check.

Explanation: PRINT. The device being used for background
printing is off line. This message only appears when the
device is off line and you enter a new PRINT command.

Action: Make sure the printing device is connected and
switched on.

EXE and HEX files cannot be written

Explanation: DEBUG. This error normally occurs when you
load a .HEX or .EXE file, modify it, and then attempt to
write the file back to a diskette.

You should understand that .EXE and .HEX files contain
loading information that is used to load the file. When
DEBUG is executed, it loads the .EXE file while at the
same time discarding the information. During direct
execution of an .EXE file, the same thing happens. When
you use DEBUG to write an .EXE file, the information is
gone; therefore, a correct .EXE file cannot be generated.
That is why you get this error message.

A-43

The error might also be caused by the fact that the data
consists of a .COM file loaded in with DEBUG and you are
now trying to write it to an .EXE or HEX file. This is not
possible. The data requires a backward conversion that
DEBUG doesn't support.

Action: Rename the file using a different extension, then
execute DEBUG. DEBUG then reads the file in instead of
loading it, and the file can now be written out. Reading the
file in does not alter the records or data in the file.

Extender card switches do not match the system memory size

Explanation: VDISK. The Extender card switch settings do
not reflect the total amount of memory in the system unit.
Although the extender card switch settings may be set
correctly for your system, VDISK does not support memory
in an expansion unit.

Action: Check the settings on the extender card.

EXEC failure

Explanation: Commands. DOS encountered an error while
reading a command from disk, or the FILES = command in
the configuration file (CONFIG.SYS) does not specify a
large enough value.

Action: Increase the FILES= value. Restart DOS. If
restarting DOS does not work, then there may be a problem
with the disk itself.

A-44

File allocation table bad, drive x
Abort, Retry, Ignore?

Explanation: DOS.

Action: See the message Disk error reading drive x under
"Device Error Messages" at the beginning of this appendix.
If this error persists, the disk is unusable and should be
formatted again.

File AND File

Explanation: COMP. Informational message. This message
indicates the full path and filenames of the two files being
compared.

Action: No action required.

File xxx canceled by operator

Explanation: PRINT. Informational message. This message
appears on the printer after you cancel the printing of a file
to serve as a reminder that the printout is incomplete.

Action: No action required.

File Cannot be Converted

Explanation: EXE2BIN.
Action: No action required.

A-45

File cannot be copied onto itself

Explanation: COPY. You tried to COPY a file and place the
copy (with the same name as the original) in the same
directory and on the same disk as the original file.

Action: Change the name given to the copy, or put it in a
different directory, or put it on another disk.

File creation error

Explanation: DOS and commands. An unsuccessful attempt
was made to add a new filename to the directory or to
replace a file that was already there.

Action: If the file was already there, check whether the file
is marked read only and cannot be replaced. Otherwise, run
CHKDSK to determine if the directory is full, or if some
other condition caused the error.

File is cross-linked:
on cluster xx

Explanation: CHKDSK. This message appears twice for
each cross-linked cluster number, naming the two files in
error. The same data block is allocated to both files.

Action: No corrective action is taken automatically. You
must correct the problem by doing the following:

1. Make copies of both files (use COPY command).

2. Delete the original files (use ERASE command).

3. Review the files for validity and edit as necessary.

A-46

filename is currently being printed
filename is in queue

Explanation: PRINT. Informational message. These
messages appear together when you issue a PRINT
command with no parameters. They occur individually
when you queue the first or a subsequent file for printing.

Action: No action required.

File is READ-ONLY

Explanation: EDLIN. The file you specified is read-only.

Action: Use the ATTRIB command to change the attribute
of the file to read-write.

File name must be specified

Explanation: EDLIN. You typed EDLIN without specifying
the file that you wanted to edit.

Action: Type the filename on the command line when you
use EDLIN.

File not found

Explanation: DOS and commands. A file named in a
command or command parameter does not exist in the
directory of the specified (or default) drive.

Action: Retry the command using the correct filename.

A-47

File not in print queue

Explanation: PRINT. The file you want to cancel is not in
the print queue.

Action: No action required.

File sharing conflict

Explanation: COMP. Unable to compare files because one
file is in use by another process.

Action: Try the compare again at a later time.

Files are different sizes

Explanation: COMP. Informational message. The sizes of
the files to be compared do not match. This means that a
comparison cannot be done because one of the files
contains data which does not match the data in the other
file.

Action: No action required.

Files compare OK

Explanation: COMP. Informational message. The two files
just compared contain identical information.

Action: No action required.

Files were backed up xx/xx/xx

Explanation: RESTORE. Informational message telling you
the date the files were backed up on.

Action: No action required.

A-48

First cluster number is invalid,
entry truncated

Explanation: CHKDSK. Informational message. The file
whose name precedes this message contains an invalid
pointer to the data area. If you specify /F parameter the
file will be truncated to a zero length file.

Action: No action required.

Fixed Backup device is full

Explanation: BACKUP. The fixed disk media target is full.
Therefore, no more files can be backed up onto that device.

Action: No action required.

Fixed disk already has a DOS partition.

Explanation: FDISK. You chose the "Create DOS
Partition" option for a fixed disk that already has a DOS
partition.

Action: Return to the Main Menu and choose option 4,
Display Partition Data. Read Chapter 3 before continuing.

Fixup offset exceeds field width near xxxx in
xxxxxx offset xxxx

Explanation: LINK. Some possible causes: 1) A group is
larger than 64K bytes. 2) The linker has been asked to fix
up an intersegment short jump or intersegment short call.
3) A data item's name conflicts with that of a subroutine in
a library included in the link. 4) In an assembly language
source file, the user has an EXTRN declaration inside the
body of a segment. 5) A data item (DB, DW, etc.) was
declared outside all segments.

Action: Revise the source and recreate the object file.

A-49

Fixups needed - base segment (hex):

Explanation: EXE2BIN. The source (.EXE) file contains
information indicating that a load segment is required for
the file.

Action: Specify the absolute segment address at which the
finished module is to be loaded.

Note: We do not recommend using such a program as
a .COM file because the program is dependent upon
being loaded at a specific memory location.

FOR cannot be nested

Explanation: BATCH. More than one FOR subcommand
was found on one command line in the batch file.

Action: Use only one FOR subcommand per command line.
Then retry command.

Format failure

Explanation: FORMAT. A disk error was encountered
while creating the target disk.

Action: The disk is unusable. Use another disk and retry the
command.

Formatting while copying

Explanation: DISKCOPY. Informational message. The
target diskette was found to contain unformatted tracks.
DISKCOPY will format the remainder of the target diskette
as it copies data.

Action: No action required.

A-50

Note: If this message is followed by the message
Incompatible drive types, you tried to copy a dual-sided
diskette to a drive that does not have dual-sided
capability. This cannot be done. Processing ends and
the target diskette contains no useful data.

Has invalid cluster, file truncated

Explanation: CHKDSK. The file name preceding this
message means that the file contains an invalid pointer to
the data area.

Action: Use the /F parameter to truncate the file at the last
valid data block. No corrective action occurs if CHKDSK is
executed without the /F parameter.

Illegal Device Name

Explanation: MODE. The specified printer must be:

. LPT1:

. LPT2:

or,

. LPT3:

The specified Asynchronous Communications Adapter must
exist and be:

. COM1:

or,

A-51

. COM2:

There must be no more than one blank between MODE and
its parameters.

Action: Use the correct device name and retry the
command.

Incompatible system size

Explanation: SYS. The target diskette contained a copy of
DOS that is smaller than the one being copied. The system
transfer does not take place.

Action: Format a blank diskette (use the FORMAT /S
command) and then copy any files to the new diskette.

Incorrect DOS version

Explanation: Commands. The command you just entered
requires a different version of DOS than the one you are
using.

Action: Obtain correct version of DOS and retry command.

Incorrect DOS version, use DOS 2.00 or later

Explanation: LINK. Linker will not run on versions of DOS
prior to DOS 2.00.

Action: Reboot your system with DOS 2.00 or a later
version, and try linking again.

Incorrect parameter

Explanation: SHARE. A parameter specified in the SHARE
command is invalid.

Action: Check the command syntax and retry the command.

A-52

Infinite retry on parallel printer time-out

Explanation: MODE. "P" was specified in Option 1,
requesting continuous retry on time-out errors.

Action: No action required.

Insert backup diskette xx in drive x:
Strike any key when ready

Explanation: RESTORE.

Action: Insert the backup diskette(s) in sequence in
accordance with the prompt. Press any key and RESTORE
will continue.

Insert backup source diskette in drive x
Strike any key when ready

Explanation: BACKUP. Informational prompt telling you to
insert the source backup.

Action: Insert the source in drive x and strike any key.

Insert backup target diskette y in drive x
Strike any key when ready

Explanation: BACKUP. Informational prompt telling you to
insert the target backup diskette.

Action: Insert the target in drive x and strike any key.

Insert disk with \ COMMAND.COM in drive A
and strike any key when ready

Explanation: DOS. DOS is attempting to reload the
command processor, but COMMAND.COM is not on the
drive that DOS was started from.

A-53

Action: Insert the DOS diskette in the indicated drive and
press any key.

Insert diskette for drive x and press any key
when ready

Explanation: DOS. In a single diskette system, Drive A: or
B:, which is not the current default drive, is being
referenced, so DOS is asking for the diskette corresponding
to that drive.

Action: If the diskette for x is different than the one
currently in the drive, insert the appropriate diskette and
press any key.

Insert disk with batch file
and strike any key when ready

Explanation: DOS. The diskette that contained the batch
file being processed was removed. The batch processor is
trying to find the next command in the file.

Action: Insert the diskette in the appropriate drive and press
any key. Processing will continue.

Insert DOS disk in x

and strike any key when ready

Explanation: FORMAT. FORMAT is trying to load the
DOS files, but the indicated drive x does not contain the
DOS diskette.

Action: Follow the prompt and insert the DOS diskette.
Press any key and processing continues.

A-54

Insert DOS diskette in drive A:
Press any key when ready . . .

Explanation: FDISK. You have successfully created the
DOS partition on the current fixed disk.

Action: Insert the DOS diskette into drive A and press any
key. This restarts your IBM Personal Computer.

The current fixed disk is now assigned a fixed disk letter and
you can now FORMAT the fixed disk.

Insert first diskette in drive x
Insert second diskette in drive x

Explanation: DISKCOMP.

Action: Insert the first (or second) of the two diskettes to be
compared into the indicated drive. One or both of these
messages is followed by the message Strike any key when
ready. Press a key and the comparison starts.

Insert last backup target in drive x

Explanation: BACKUP. Informational prompt. The /A
parameter was specified.

Action: Insert the last backup target used in the previous
backup.

Insert new diskette for drive x
and press ENTER when ready

Explanation: FORMAT. Prompt asking you to insert the
diskette you want to format.

Action: Insert the diskette you want to format and press
Enter.

A-55

Insert source diskette in drive x
Insert target diskette in drive x

Explanation: DISKCOPY.

Action: Insert the appropriate diskette into the indicated
drive, and press any key when asked. The copying process
starts.

Insert restore source xx in drive yy
Strike any key when ready

Explanation: RESTORE. This is the informational prompt
for removable media.

Action: Insert the source in drive yy and strike any key. No
action required.

Insert restore target xx in drive yy
Strike any key when ready

Explanation: RESTORE. This is the informational prompt
for removable media.

Action: Insert the target in drive yy and strike any key.

Insert System disk in x

and strike any key when ready

Explanation: SYS. SYS is trying to load the DOS files, but
the indicated drive x does not contain the DOS diskette.

Action: Follow the prompt and insert the DOS diskette.
Press any key and processing continues.

A-56

Insufficient disk space

Explanation: DOS and commands. The disk does not
contain enough free space to contain the file being written.

Action: If you suspect this condition is invalid, run
CHKDSK to determine the status of the disk. Otherwise,
use another disk and retry the command.

Insufficient memory

Explanation: Commands. The amount of available memory
is too small to allow these commands to function.

Action: Change the BUFFERS = parameter in the
CONFIG.SYS file to a smaller value (if you have specified
BUFFERS=), restart the system and try the command
again. If the message still appears, your system does not
have enough memory to execute the command.

Insufficient memory for system transfer

Explanation: FORMAT and SYS. There is not enough
memory on the disk.

Action: No action required.

Insufficient room in root directory

Erase files from root and repeat CHKDSK.

Explanation: CHKDSK. You instructed CHKDSK to create
files from the "lost" data blocks it has found, but the root
directory is full, and all of the lost chains could not be
recovered into files.

Action:

1 . Copy some of the recovered files to another disk for
further examination.

A-57

2. Delete the recovered files from the disk you are
checking.

3. Run CHKDSK again to recover the remainder of the
lost data.

Insufficient space on disk

Explanation: DEBUG. A write command was issued to a
disk that doesn't have enough free space to hold the data
being written.

Action: If you are writing to a diskette, you can insert a
diskette that has enough free space, then reissue the write
command. Otherwise, you should erase files from the disk
and run DEBUG again.

Insufficient stack space

Explanation: LINK. There is not enough memory to run the
linker.

Action: Restart the system to free some memory that was
used by installable device drivers such as VDISK, and
terminate and stay resident programs such as PRINT and
GRAPHICS.

Intermediate file error during pipe

Explanation: DOS. DOS is unable to create one or both of
its intermediate files because the default drive's root
directory was full, or DOS is unable to locate the piping
files, or the disk does not have enough space to hold the
data being piped.

Action: Erase some files from the default drive's root
directory, and reissue the command that failed. If you get
the same message, one of the programs in the command line
has erased one or both of the piping files. Correct the
program and reissue the command line.

A-58

Invalid baud rate specified

Explanation: MODE.

Action: Specify the baud rate as 110, 150, 300, 600, 1200,
2400, 4800, or 9600 (you need specify only the first two
characters of the number).

Invalid characters in volume label

Explanation: FORMAT. One or more of the characters you
entered in the volume label is not a valid filename character,
or the name contained a period (volume labels contain 1 to
1 1 valid characters without a period).

Action: Retry using valid characters.

Invalid COMMAND.COM in drive n

Explanation: DOS. When DOS tried to reload the command
processor, the copy of COMMAND.COM on the disk was
found to be an incorrect version.

Action: Insert the correct DOS diskette and press any key to
continue.

Invalid country code

Explanation: SELECT, COUNTRY. The country code
specified in COUNTRY= command in CONFIG.SYS or
input to the SELECT command is not available.

Action: See SELECT command in Chapter 7 or "Creating
a CONFIG.SYS File" in Chapter 4 for the correct country
code and try again.

A-59

Invalid current directory

Explanation: CHKDSK. CHKDSK attempted to read the
current directory. It found an unrecoverable error on the
disk.

Action: No action required.

Invalid date

Explanation: DATE. You entered an invalid date or
delimiter. The only valid delimiters in a date entry are
hyphens (-) and slashes (/).

Action: Re-enter valid date.

Invalid device

Explanation: CTTY. The device name you specified is an
invalid name to DOS.

Action: Retry command using valid device name.

Invalid directory

Explanation: DOS and commands. One of the directories in
the specified path does not exist.

Action: Retry command using valid directory.

Invalid disk change

Explanation: The diskette in the high-capacity drive was
changed while files were still open on the diskette.

Action: Reinsert the correct diskette.

A-60

Invalid drive in search path

Explanation: DOS. An invalid drive specifier was found in
one of the paths specified in the PATH command.

This message appears when DOS attempts to locate a
command or batch file, not at the time you issued the
erroneous PATH command.

Action:

1. Enter PATH. This displays the PA THs you previously
defined.

2. Find the invalid specifier.

3. Re-enter the PATH command with the valid drive
specifier and the paths you desire.

Invalid drive or filename

Explanation: RECOVER. The drive or filename specified is
invalid.

Action: No action required.

Invalid drive specification
Specified drive does not exist,
or is non-removable

Explanation: DOS and commands. An invalid drive
specification was just entered in a command or in one of its
parameters.

Action: Re-enter the command using a valid drive specifier.

A-61

Invalid drive specification

Source and Target drives are the same

Explanation: BACKUP and RESTORE. You cannot have
the same drive specifiers for the source and target drives.

Action: Specify a different drive letter for the source and
target drives.

Invalid filename or file not found

Explanation: RENAME or TYPE. You tried to rename a
file that was either invalid or not found in the specified
directory.

TYPE does not allow global filename characters.

Action: No action required.

Invalid format file

Explanation: LINK. A library is in error.

Action: Restore library file from your backup disk and try
again.

Invalid media or track bad - disk unusable

Explanation: FORMAT. FORMAT was unable to format
track on the specified media. This error occurs if:

• Track is unusable. Track is where the boot record,
file allocation table, and directory must reside. If track
is bad, the disk is unusable.

• The diskette type and drive type are incompatible. You
tried to format a double-sided diskette in a
high-capacity drive, or a high-capacity diskette in a
double-sided drive.

A-62

Action: For the first case, obtain another disk and retry the
FORMAT command. For the second case, retry the
FORMAT command specifying the /4 parameter.

Invalid number of parameters

Explanation: Commands. You have specified too few or too

many parameters for the command you issued.

Action: Review this command in the "Commands" section
of this book.

Invalid numeric parameter

Explanation: LINK. The numeric value is not in digits.

Action: Run LINK again and name the numeric parameter
with values of through 9 for each digit.

Invalid numeric switch specification
switch error: "s: xxx"

Explanation: LINK. Typographical error entering value for
one of the LINKER switches, such as entering a character
string for a switch that requires a numeric value.

Action: No action required. Linker will abort.

Invalid object module

Explanation: LINK. Object module(s) was incorrectly
formed or unobserved errors occurred during compilation.
The disk may be bad.

Action: Recompile the module to either the same or a
different disk.

A-63

Invalid parameter

Explanation: DOS and commands. One or more of the
parameters entered for these commands is not valid.

Action: If the program expects a drive specifier, enter a
colon following the drive letter. In other cases, make sure
the character following the slash (/) is valid for the program
being run. For JOIN and SUBST see the specific command
in Chapter 7 for valid parameters.

Invalid parameters

Explanation: MODE.

• No parameters were entered

• The first parameter character was other than L, or C

• The first parameter was other than 40, 80, BW40,
BW80, CO40, CO80, MONO, L, R

• The display adapter the parameter refers to is not
present in the machine.

Action: Check the preceding list and correct accordingly.

Invalid partition table

Explanation: Start-up. While attempting to start DOS from
your fixed disk, the start-up procedures detected invalid
information in the disk's partition information.

Action:

1 . Start DOS from the diskette.

2. Use the FDISK command to examine and correct the
fixed disk partition information.

A-64

Invalid path

Explanation: TREE, BACKUP, RESTORE. The command
was unable to use a directory whose name was found in
another directory.

Action: Run CHKDSK to find out what is wrong with the
directory structure.

Invalid path, not directory
or directory not empty

Explanation: RMDIR.

• The specified directory was not removed because one
of the names you specified in the path was not a valid
directory name.

or,

• The directory you specified still contains entries for
files or other subdirectories (with the exception of the
and .. entries).

• You cannot remove a current directory.
Action: Try one of the following:

• Correct the invalid directory name in the path.

• Delete any files or remove any subdirectories in the
directory.

• Change to a different subdirectory and try again.

A-65

Invalid path or file name

Explanation: ATTRIB or COPY. You specified a directory
or file name that does not exist.

Action: Use correct name. Check for the following. Then
retry command:

• Correct spelling of names

• Valid directory names

• Existence of file in the subdirectory specified
Invalid subdirectory

Explanation: CHKDSK. Invalid information was detected in
the subdirectory whose name precedes this message.

Action: CHKDSK attempts to correct the error if you have
used the /F parameter. For more specific information
about the nature of the error, run CHKDSK with the /V
parameter.

Invalid switch

Explanation: LINK. The character indicated on the
preceding line is not a valid linker parameter (switch).

Action: Review Chapter 9, "The Linker (Link) Program" to
determine which characters are a valid link parameters
(switches).

Invalid switch character

Explanation: VDISK. VDISK encountered a forward slash
in the DEVICE=VDISK.SYS CONFIG.SYS command, but
the following character was not an E. VDISK will attempt
to install the virtual disk in low memory.

A-66

Action: No action required.
Invalid time

Explanation: TIME. An invalid time or delimiter was
entered.

Action: Re-enter the correct time. The only valid delimiters
are:

• A colon (:) between the hours and minutes

• A colon (:) between the minutes and seconds

• A period (.) between the seconds and hundredths of a
second.

Label not found

Explanation: Batch. Informational message. A GOTO
command named a label that does not exist in the batch file.
This caused the system to read to the end of the batch file,
ending batch processing.

Action: If you do not want the GOTO to exit the batch file,
edit the batch file and put the label in the desired location.

Last backup target not inserted

Explanation: BACKUP. The /A parameter was specified,
but the removable target was not the last in the backup
sequence.

Action: No action required.

A-67

*** Last file not backed up ***

Explanation: BACKUP. The fixed target became full while
the file was being backed up. There is no room for the
entire file, so the backup file is deleted and this message is
issued.

Action: No action required.

Line too long

Explanation: EDLIN. Upon replacing a string, the
replacement caused the line to expand beyond the
253-character limit. The REPLACE text command is
ended abnormally.

Action: Split the long line into shorter lines; then issue the
REPLACE text command again.

List output is not assigned to a device

Explanation: PRINT. The list device specified is not a valid
device to PRINT to.

Action: Invoke PRINT again and specify a valid list device.
Trailing colon is not needed.

LPT#: not rerouted.

Explanation: MODE. Informational message. The parallel
printer will now receive its own output, even if this printer's
output had previously been rerouted to a serial device.

This message is provided for your information and indicates
cancellation of any previous redirection that may have been
in effect, because you have set the printer width or vertical
spacing.

Action: No action required.

A-68

LPT#: rerouted to COM/?:

Explanation: MODE. Informational message

This message is provided for your information and indicates
that any request that would normally have gone to the
parallel printer LPT# (#= 1, 2, or 3) is sent instead to the
serial device COMn {n=\ or 2).

Action: No action required.

LPT#: set for 80

Explanation: MODE. Informational message. You tried to
set the printer line length to 80 characters by requesting
standard type format.

This message is provided for your information. If the
attempt was unsuccessful, an error message will follow this
message on the screen.

Action: No action required

LPT#:setforl32

Explanation: MODE. Informational message. You tried to
set the printer line length to 132 characters by requesting
compressed type format.

If the attempt is unsuccessful, an error message will follow
this message on the screen.

Action: No action required.

A-69

Make sure a diskette is inserted into
the drive and the door is closed

Explanation: DISKCOMP and DISKCOPY. The drive is
empty or the drive door is left open.

Action: Insert a diskette or close the drive door.

Maximum available space is xxxx
cylinders at cylinder xxxx.

Explanation: FDISK. Informational message. The "Create
DOS Partition" option displays the largest available piece of
space on the current fixed disk. These numbers are also
used as the defaults for the two prompts that will follow.

Action: No action required.

Memory allocation error

Cannot load COMMAND, system halted

Explanation: DOS. A program destroyed the area in which
DOS keeps track of available memory.

Action: Restart DOS.

Mismatch DOS level number

Explanation: LINK. Internal linker error.

Action: Record the scenario that produced this message, and
contact your IBM dealer.

A-70

Missing operating system

Explanation: Startup. When you tried to start DOS from
fixed disk, the startup procedures determined that the DOS
partition was marked "bootable" (startable), but that it
doesn't contain a copy of DOS.

Action: Start DOS from diskette and use FORMAT with the
/S parameter to place a copy of DOS on the fixed disk.
You should back up your files before doing the FORMAT
or they will be lost.

Must specify ON or OFF

Explanation: BREAK. You entered something other than
on or off.

Action: Try again, specifying on or off.

Must specify destination line number

Explanation: EDLIN. A Move or Copy command was
entered without a destination line number.

Action: Re-enter the command with a valid destination line
number.

Name of list device [PRNJ:

Explanation: PRINT. This message appears the first time
you start print after DOS has been restarted.

Action: Reply with the reserved device name which is to
receive the printed output, or simply press Enter if the first
parallel printer [PRN] is to be used.

A-71

NEAR/FAR conflict

Explanation: LINK. Conflicting near and far definitions for
a communal variable.

Action: Revise definitions to be consistent.

Network support loaded
Unable to FDISK

Explanation: FDISK. FDISK cannot modify a remote fixed
disk.

Action: Restart system without Network support and try
FDISK again.

No DOS partition to delete.

Explanation: FDISK. You chose the "Delete DOS
Partition" option but there was no DOS partition on the
current fixed disk.

Action:

1 . Return to the Main Menu.

2. Select the Display Partition Data to review.

3. Proceed with your next choice.

No free file handles

Cannot start COMMAND, exiting

Explanation: DOS. An attempt to load a second copy of the
command processor failed because there are too many files
open.

Action: Increase the number in the FILES = command in
the configuration file (CONFIG.SYS), and restart DOS.

A-72

No fixed disks present

Explanation: FDISK. The FDISK program was run on an
IBM Personal Computer that:

• Does not have a fixed disk, or

• Has a fixed disk in the expansion unit and the
expansion unit is not powered on, or

• Has a fixed disk that is not properly installed.

Action: From the above list find out what caused the
problem and take appropriate action. Check to make sure
the expansion unit is powered ON first.

No object modules specified

Explanation: LINK. You did not name any object modules
in the command line or in response to the prompt.

Action: Name the object modules, since the linker needs
some files to link.

No partitions to make active.

Explanation: FDISK. You chose the "Change Active
Partition" option but there were no partitions on the current
fixed disk to be made active.

Action: Use the "Create DOS Partition" option to create a
partition, then the "Change Active Partition" option to
make it the active partition.

A-73

No path

Explanation: PATH. Informational message. There is
currently no alternate path for DOS to search to find
commands and batch files if it does not find them in the
specified (or current directory).

Action: Informational message unless you want to define a
set of paths. If so, enter PATH and the set of paths you
want. Then press Enter.

No retry on parallel printer time-out

Explanation: MODE. P was not specified in Option 1,
requesting no retry on time-out errors.

Action: No action required.

No room for system on destination disk

Explanation: SYS. The destination diskette does not contain
the required reserved space for DOS; therefore, the system
cannot be transferred.

Action: Format a blank diskette (use the FORMAT /S
command), then copy any other files to the new diskette.

No room in directory for file

Explanation: EDLIN. The directory on the specified disk is
full. Your editing changes are lost.

Action: Make sure that your disk has available directory
entries and run EDLIN again.

A-74

No room in root directory

Explanation: LABEL. An error occurred while creating the
volume label, probably due lack of room in the root
directory for another entry.

Action: If the length of the label is less than 1 1 characters,
and you used only valid filename characters (no periods),
then delete a file from the root directory to make room for
another entry. Try LABEL again.

No space for a xxxx cylinder partition.

Explanation: FDISK. You entered a "Partition Cylinder
Size" that is larger than the largest piece of free space on
the disk.

Action: Enter a smaller number.

No space for a xxxx cylinder partition
at cylinder xxxx

Explanation: FDISK. You requested a partition to be
created at a place on the current fixed disk and there is no
space at that place to create a DOS partition.

Action: Look for typographical errors. Reinvestigate your
partitioning requirements.

No space to create a DOS partition

Explanation: FDISK. You chose the "Create DOS
Partition" option on the current fixed disk which has no
space to create a DOS partition.

Action: Remove or reduce the size of the existing partition.
Then run FDISK again to create the DOS partition(s).

A-75

No subdirectories exist

Explanation: TREE. Informational message. The specified
drive contains only a root directory. Therefore, there is no
directory path to display.

Action: No action required.

Non-DOS diskette

Explanation: CHKDSK and Commands. The format of the
diskette accessed was not recognized.

Action: Format the diskette using the FORMAT command.

Non-System disk or disk error
Replace and strike any key when ready

Explanation: Startup. No entry exists for IBMBIO.COM or
IBMDOS.COM in the directory; or a disk read error
occurred when you started up the system.

Action: Insert a DOS diskette in drive A and then restart
your system.

*** Not able to back up file ***

Explanation: BACKUP. The files cannot be backed up due
to a file sharing conflict.

Action: Retry the request at a later time by specifying the
same backup command but include the /M parameter.

A-76

*** Not able to restore file ***

Explanation: RESTORE. The file you want to restore
cannot be opened due to a sharing conflict.

Action: No action required.

Not enough memory

Explanation: SHARE,REDIR. The available memory is less
than what SHARE and REDIR need to start. They
terminate without installation.

Action: No action required.

Not enough room to merge the entire file

Explanation: EDLIN. Informational message. A Transfer
command was unable to merge the entire contents of the
specified file because of insufficient memory. Only part of
the file was merged.

Action: Either reduce size of one of the files being merged,
or install more memory.

Not found

Explanation: EDLIN. Informational message. Edlin could
not find the string specified by the REPLACE text or
SEARCH text commands within the specified range of
lines. Or, if a search is resumed by replying N to the OK?
prompt, no further occurrences of the string were found.

Action: Check to be sure you properly used upper and lower
case for the string to be searched.

A-77

Out of environment space

Explanation: DOS. Informational message. DOS was
unable to accept the SET command you just issued because
it was unable to expand the area in which the environment
information is kept.

This normally occurs when you try to add to the
environment after loading a program which makes itself
resident (PRINT, MODE, or GRAPHICS for example).

Action: No action required.

Out of space on list file

Explanation: LINK. There is not enough disk space for the
list file.

Action: Use a disk with enough free space to hold the file.

Out of space on run file

Explanation: LINK. This error usually occurs when there is
not enough disk space for the Run file (.EXE).

Action: Use a disk with enough free space to hold the file.

Out of space on scratch file

Explanation: LINK. The disk that the linker is using for
scratch file is full.

Action: Delete some files on that disk, or replace with
another diskette, and restart the linker.

A-78

Out of space on VM.TMP

Explanation: LINK. No more disk space remained to
expand the VM.TMP file.

Action: Use a disk with enough free space to hold this file.

Parameters not compatible

Explanation: FORMAT. You attempted to use two
parameters that are not compatible with each other (/B and
/V for example).

Action: Review the FORMAT command. Correct
parameter and re-enter the command.

Parameter not compatible with fixed disk

Explanation: FORMAT. You wrongly specified the /l or
/8 parameter while formatting a fixed disk. Neither of
these parameters is valid for a fixed disk.

Action: Review the FORMAT command. Correct
parameter and re-enter the command.

Parity error or nonexistent memory error detected

Explanation: DEBUG.
Action: No action required.

A-79

Partition 1 is already active

Explanation: FDISK. Informational message. Partition 1 is
the only partition defined and it is already marked as active.

Action: No action required.

Partition xx made active

Explanation: FDISK. Informational message. Partition xx is
now marked as bootable.

Action: No action required.

Path not found

Explanation: DOS and commands. A file or path named in a
command or command parameter does not exist in the
directory of the specified (or default) drive.

Action: Retry the command using the correct path and
filename.

Pathname too long

Explanation: PRINT. The path for the file you specified is
longer than 64 characters.

Action: No action required.

Please replace original diskette
in drive A: and press <ENTER>

Explanation: LINK. This message appears after the .EXE
file has been written if the /P switch is given.

Action: Insert the diskette with the list file so that it can be
reopened.

A-80

Press any key to begin formatting x:

Explanation: FORMAT. The fixed disk (drive x) is about to
be formatted. Formatting will lose track of all previously
existing data on the disk.

Action: If you do not want the disk formatted, press
Ctrl-Break. If you do want the disk formatted, press a
character key.

Press any key to begin recovery
of the file(s) on drive x

Explanation: RECOVER.

Action: Insert the diskette to be recovered in the indicated
drive and press any character key.

Print queue is empty

Explanation: PRINT. Informational message. There are
currently no files being processed by PRINT.

Action: No action required.

Print queue is full

Explanation: PRINT. You tried to add more than the limit
of ten files to the print queue. Ten files is the default. You
can set the limit to 32 files. See the PRINT command.

Action: Wait until a file is printed before you add another
file to the print queue.

A-81

Printer error

Explanation: MODE. The MODE command (option 1) was
unable to set the printer mode because:

• There is an I/O error

• The printer is out of paper (or POWER OFF)

• There is a printer time out (not ready) condition

• The printer is offline

Action: Determine which of above conditions caused the
error message and take corrective action.

Printer lines per inch set

Explanation: MODE. Informational message. You tried to
set the printer vertical spacing to the specified 6 or 8 lines
per inch.

Action: If the attempt was unsuccessful, an error message
follows this message on the screen.

Probable non-DOS disk
Continue (Y/N)?

Explanation: CHKDSK. The file allocation table
identification byte contains invalid information. Either the
disk was not formatted by DOS or has become badly
damaged.

Action: If you did not use the /F parameter, and you reply
Y, CHKDSK will indicate its possible corrective actions
without actually changing the disk. We recommend doing
this first, before you consider using the /F switch and
replying Y.

A-82

Processing cannot continue

Explanation: CHKDSK. Informational message. This
message is followed by another message which explains why
CHKDSK cannot continue.

This message is normally issued when there is not enough
memory.

Action: No action required.

Program size exceeds capacity of LINK, limit 704K

Explanation: LINK. Load module was too large for
processing.

Action: Reduce the size of the program.

Program terminated normally

Explanation: DEBUG. This message informs you that the
program that was executed by issuing G(o),T(race), or
P(roceed) has completed via an INT 20, INT 27, INT 21, or
other expected manner.

Action: No action required.

Program too big to fit in memory

Explanation: DOS. The file containing the external
command cannot be loaded because it is larger than the
available free memory.

Action: Reduce the number in the BUFFERS = parameter in
your CONFIG.SYS file (if you have specified
BUFFERS=), restart your system, and reissue the
command.

A-83

If the message reappears, your system does not have enough
memory to execute the command.

Read error in:
x:\level 1\ level 2.

Explanation: EDLIN. An error occurred while reading file
x:\xxxx\xxxx into memory.

Action: Copy the file or a backup of the file to a different
disk and try again.

Reinsert diskette for drive x
and strike Enter when ready

Explanation: FORMAT. This message, which usually
occurs after you enter FORMAT /S, means:

• DOS filled the memory with system files, but could not
read all of the files, into memory because of insufficient
memory size.

• After asking for the new diskette, FORMAT started
formatting it and all of the files in memory on the new
diskette.

• FORMAT then asked that the DOS diskette be
inserted so it could finish loading the rest of the DOS
files into the memory.

Action: FORMAT is now asking you to insert the new
diskette again so it can finish the task of writing the DOS
files onto the new diskette.

A-84

Relocation table overflow

Explanation: LINK. More than 13000 long calls or long
jumps or other long pointers in the program.

Action: Rewrite program replacing long references with
short references where possible and recreate object module.
Note: Pascal and FORTRAN users should first try turning
debugging off.

Resident part of PRINT installed

Explanation: PRINT. Informational message. The message
appears the first time you use the PRINT command.

This message indicates that a program has been loaded into
memory to handle subsequent PRINT commands.
Available memory for your applications has been reduced
by approximately 3200 bytes.

Action: No action required.

Resident portion of MODE loaded

Explanation: MODE. Informational message.

This message indicates that when MODE is invoked for a
non-screen-setting function it is sometimes necessary to
load a portion of code to be made permanently resident.

Action: No action required.

Restore file sequence error

Explanation: RESTORE. The file was not restored because
the diskettes were not inserted in sequential order.

Action: Retry the restore, inserting the diskettes in
sequential order.

A-85

*** Restoring files from drive y ***
Source: x

Explanation: RESTORE. This is an informational message
telling you that the files on the source drive are being
restored.

Action: No action required.

Sector size adjusted

Explanation: VDISK. VDISK found it necessary to adjust
the sector size value in the DEVICE = VDISK. SYS in the
CONFIG.SYS command.

Action: No action required.

Sector size too large in file < filename >

Explanation: Startup. The device driver named in

< filename > specifies a device sector size larger than the

devices previously defined to DOS.

Action: Reduce sector size to conform with the sector size
of DOS.

If this is a purchased program, return it to your dealer.

Segment limit set too high, exceeds 1024

Explanation: LINK. The count specified for segments in the
/X: parameter is too large.

Action: No action required. Linker will abort.

A-86

Segment limit too high

Explanation: LINK. There is insufficient memory for the
linker to allocate tables to describe the number of segments
requested (either the value specified with /X or the default:
256).

Action: Either try the link again using /X to select a smaller
number of segments (e.g. 128, if the default was used
previously) or restart the system to free some memory that
was used by installable device drivers such as VDISK,
and terminate and stay resident programs such as PRINT
and GRAPHICS.

Segment size exceeds 64K

Explanation: LINK. This message indicates that you
attempted to combine identically named segments which
resulted in a segment requirement of greater than 64K
bytes. You cannot address more than 64K bytes.

Action: Change segment names in object modules and try
link again.

Source and target drives are the same

Explanation: BACKUP and RESTORE. The drive specifier
for the source and target drive cannot be the same.

Action: Specify a different drive letter for the source and
target drives.

Source does not contain backup files

Explanation: The source media does not contain files created
by the BACKUP command.

Action: No action required.

A-87

SHARE already installed

Explanation: SHARE. You have already loaded SHARE.
SHARE can only be loaded once when you start DOS.

Action: No action required.

Sharing buffer exceeded

Explanation: The buffer area for file sharing and block
locking was exceeded.

Action: Choose Retry. If the error reoccurs and you're usin£
the PC Network Program, restart the server and increase
/SHB and /SHL on NET START. If you're not using the
network, restart DOS and increase /F and /L on SHARE.

Specified command search directory bad

Explanation: Commands. Invalid path name specified.

Action: Specify valid path name containing command
processor.

Specified drive does not exist,
or is non-removable

Explanation: DISKCOPY and DISKCOMP. The drive
specifier is for a fixed disk drive, or does not exist on your
computer.

Action: Check the drive specifier and reenter the command.

Source diskette bad or unusable

Explanation: DISKCOPY. Read errors on the source
diskette indicate that it may not be suitable for a
DISKCOPY.

A-88

Action: Make sure that there is no necessary data on the bad
part of the diskette, and compare the files copied to assure
that the copy was successful.

Stack size exceeds 65536 bytes

Explanation: LINK. Informational message. The size
specified for the stack must be less than or equal to 65536.

Action: No action required.

Symbol defined more than once

Explanation: LINK. The Linker found two or more modules
that define a single symbol name.

Action: Make sure you're not linking the same files twice.
Make sure one of the modules does not have a symbol
incorrectly identified as public instead of external. Does one
of the modules being linked have a symbol incorrectly
identified as public instead of external?

Symbol table overflow

Explanation: LINK. The user's program has greater than
25 6K of symbolic information (publics, externs, segments,
groups, classes, files).

Action: Combine modules and/or segments and recreate the
object files. Eliminate as many public symbols as possible.

Syntax error

Explanation: DOS. The command format you typed is
improper.

Action: Check to make sure you have used the correct
format for this command.

A-89

System files restored

The target disk may not be bootable

Explanation: RESTORE. DOS system files IBMBIO.COM
or IBMDOS.COM were restored. The diskette may not be
bootable if the system files from a previous version of DOS
were restored.

Action: SYS the disk with DOS Version 3.00 and copy
COMMAND.COM to the root directory of the target disk.

System transferred

Explanation: FORMAT. This message is displayed when
you specify FORMAT /S. It is an informational message
telling you that the system files have been installed on the
formatting disk.

Action: No action required.

System will now restart

Insert DOS diskette in drive A:

Press any key when ready

Explanation: FDISK. Informational message. FDISK
requires the system to restart in order to update the
partition information.

Action: Place DOS diskette in drive A: and press any key.

Target can not be used for backup

Explanation: BACKUP. Your attempt to create files on the
target disk failed.

Action: Replace the disk if it is removable. If not, BACKUP

A-90

to a different device or restart the system and try again.
Target diskette bad or unusable

Explanation: DISKCOPY. Errors encountered during the
copy indicate that the target diskette is dirty, damaged or of
poor quality, or the drive is malfunctioning on some tracks.

Action: Change the target drive or the diskette and try
again.

Target diskette may be unusable

Explanation: DISKCOPY. This message follows an
unrecoverable read, write, or verify error message. The
copy on the target diskette may be incomplete because of
the unrecoverable I/O error.

Action:

If error is on the target diskette, get a fresh diskette for
your target, and retry the DISKCOPY command.

If the error is on the source diskette, copy all files from
the source diskette to another diskette. Then try to
reformat the source diskette.

A-91

Target diskette write protected
Correct, then strike any key

Explanation: DISKCOPY. You are trying to produce a copy
on a diskette that is write protected.

Action: Either remove the write protect tab, or use another
diskette that is not write protected.

Target does not contain backup files

Explanation: BACKUP. The /A parameter was specified,
but no previously backed up files were found on the target
drive.

Action: No action required.

Target is full

Explanation: RESTORE. The disk you are restoring to is
full.

Action: Delete any unnecessary files you have and try again,
or RESTORE to a destination disk with more space.

Terminate batch job (Y/N)?

Explanation: DOS. This message appears when you press
Ctrl-Break while DOS is processing a batch file.

Action: Press Y to stop processing the batch file. Pressing
N only ends the command that was executing when
Ctrl-Break was pressed; processing resumes with the next
command in the batch file.

A-92

Terminated by user

Explanation: LINK. The user entered Ctrl-Break in
response to one of the linker prompts.

Action: No action required.

The current active partition is x.

Explanation: FDISK. Informational message. The "Change
Active Partition" option displays the active partition on the
current fixed disk.

Action: No action required.

The last file was not restored

Explanation: RESTORE. You stopped RESTORE before it
completely restored the last file listed, or there was not
enough room on the fixed disk and RESTORE deleted the
partially restored file.

Action: If RESTORE has ended, you can re-enter the
RESTORE command with the filename of the file(s) not
restored to continue from the point where RESTORE
stopped.

If the problem occurred because you ran out of room on the
fixed disk, you must evaluate which files to keep and which
ones to delete. Then continue the execution of RESTORE.

There was/ were number errors detected

Explanation: LINK. This message is displayed for your
information at the end of the link session.

Action: No action required.

A-93

Too many block devices

Explanation: CONFIG.SYS. You attempted to install more
than the system limit of 26 block device units.

Action: Change your CONFIG.SYS "DEVICE="

command so that only 26 block device units (including
those automatically installed by DOS for disk/diskette
drives) are installed. See Chapter 4, "Configuring Your
System," of the DOS Reference, and Chapter 2, "Installable
Device Drivers," of the DOS Technical Reference for more
information.

Too many external symbols, limit 510 per module

Explanation: LINK. More than the limit of 510 external
symbols were specified in a module.

Action: Break up the module.

Too many files open

Explanation: EDLIN. EDLIN tried to open the specified
file, but was not able to.

Action: Increase the FILES= value in the CONFIG.SYS
file.

Too many group-, segment-, and class-names, limit 254 per
module

Explanation: LINK. User's program contains too many
group, segment, and class names.

Action: Reduce the number of groups, segments, or classes
and recreate the object files.

A-94

Too many groups

Explanation: LINK. The limit is 9 including DGROUP.
This message indicates that the limit was exceeded.
Action: Reduce the number of groups.
Too many GRPDEFs, limit 8 per module.

Explanation: LINK. Linker encountered more than 8
GRPDEFs in a single module.

Action: Reduce the number of groups or split up the
module.

Too many libraries, limit is 16

Explanation: LINK. User tried to open more than 16
libraries.

Action: Combine libraries or link modules that require fewer
libraries.

Too many overlays

Explanation: LINK. The limit is 64 overlays. This message
indicates that the limit was exceeded.

Action: Reduce the number of overlays.

Too many public symbols

Explanation: LINK. The limit is 2048 public symbols. This
message indicates that the limit was exceeded.

Action: Reduce the number of public symbols.

A-95

Too many segments, limit 255 per module

Explanation: LINK. The user's object module has more
than 255 segments.

Action: Split the modules or combine segments.

Too many segments, use /X:N (256<N<1025)

Explanation: LINK. The user has specified more than the
maximum of 1024 segments.

Action:Relink using the /X parameter with appropriate
number of segments specified.

Too many TYPDEFs, limit 255 per module

Explanation: LINK. TYPDEFs are records emitted by the
compiler to describe communal variables.

Action: Create two sources from the old source, dividing the
communal variable definitions between them; recompile and
relink.

Top level process aborted, cannot continue

Explanation: During boot, COMMAND detected a disk
error, and you chose to ABORT. The error is
unrecoverable and COMMAND has no choice but to halt.

Action: The recommended course of action is to use another
disk.

A-96

Total disk space is xxxx cylinders.

Explanation: FDISK. Informational message. This message
shows the total space on the current fixed disk.

Action: No action required.
Transfer size adjusted

Explanation: VDISK. The maximum number of sectors to
transfer specified (m) was not in the range 1-8. The value 8
will be used by VDISK.

Action: No action required.

Tree past this point not
processed

Explanation: CHKDSK. Informational message. CHKDSK
is unable to continue processing past the directory path
currently being examined of the error displayed in the
previous message.

Action: No action required.

A-97

Unable to create directory

Explanation: MKDIR. The directory you want to create
already exists, or one of the directory path names you
specified could not be found, or you attempted to add a
directory to the root directory and it is full. Make sure a file
by that name does not already exist in that directory.

Action: Do the following:

• Check to see if a directory by that name exists in the
parent directory (or current directory)

• Recheck all your directory names to make sure they are
valid

• Use CHKDSK to see if your directory is full
Unable to write BOOT

Explanation: FORMAT. The first track of the diskette or
DOS partition is bad. The BOOT record could not be
written on it. The diskette or DOS partition is not usable.

Action: Obtain another diskette and retry the FORMAT
command.

Unable to shift screen left

Explanation: MODE. Shifting the screen further to the left
would exceed the allowable limit.

Action: No action required.

A-98

Unable to shift screen right

Explanation: MODE. Shifting the screen further to the right
would exceed the allowable limit.

Action: No action required.

Unexpected end-of-f ile on library

Explanation: LINK. Informational message. This is caused
by an error in the library file.

This usually means that the object file contains bytes that
are of the same value as end-of-file. If this occurs, LINK
continues processing to the physical end-of-file as given in
the directory.

Action: No action required.

Unexpected end-of-file on scratch file

Explanation: LINK. Diskette containing VM.TMP was
removed.

Action: Restart linker.

Unexpected end of file on VM.TMP

Explanation: LINK. Informational message. The diskette
containing VM.TMP was removed.

Action: No action required.

A-99

Unrecognized command in CONFIG.SYS

Explanation: Startup. An invalid command was detected in
the configuration file CONFIG.SYS.

Action: Edit the file, correct the invalid command, and
restart DOS.

Unrecognized switch error: xxxxxx

Explanation: LINK. User entered an unrecognized
character after the switch indicator /.

Action: No action required. Linker will abort.

Unrecoverable error on directory

Explanation: CHKDSK. CHKDSK encountered an error
while checking the directory.

Action: No action required.

Unrecoverable file sharing error

Explanation: SHARE. A file sharing conflict occurred.
Therefore, files cannot be restored.

Action: No action required.

Unrecoverable read error on drive x
Track xx, side x

Explanation: DISKCOMP. Four attempts were made to
read the data from the diskette in the specified drive. The
data could not be read from the indicated track and side.

A- 100

Action: If the error occurred on the target diskette (just
created by DISKCOPY) get a fresh diskette and retry the
DISKCOPY and DISKCOMP commands. Otherwise, use:

COPY *.*

to copy all files from the damaged diskette to another
diskette. Then reformat the bad diskette or else discard it.

Unrecoverable read error on source
Track XX, side x

Explanation: DISKCOPY. Four attempts were made to read
the data from the source diskette. DISKCOPY continues
copying, but the copy may contain incomplete data.

A-101

Action: Use the following form of the COPY comand:

COPY *.*

to copy all files from the damaged diskette to another
diskette. Reformat the bad diskette, or else discard it.

Unrecoverable write error on target
Track xx, side x

Explanation: DISKCOPY. Several attempts were made to
write the data to the target diskette. DISKCOPY continues
copying, but the copy may contain incomplete data.

Action: Obtain a fresh diskette and re-enter the DISKCOPY
command. Use FORMAT on the bad diskette to see if can
be reused. If it is a bad diskette, discard it.

Unresolved externals: list

Explanation: LINK. The external symbols listed were not
defined in the modules or library files that you specified.

Action: Do not attempt to run the executable file created by
the linker.

Make sure you specified all appropriate object modules and
libraries. Check the source code for the program that
caused the message and make corrections to that program.

VDISK not installed - insufficient memory

Explanation: VDISK. This message occurs if:

• Less than 64K of available memory would exist even
after attempting to adjust the virtual disk size and
number of directory entries.

A-102

• You have specified the /E parameter and the computer
does not contain extended memory.

• The amount of available extended memory is too small
to install the virtual virtual disk, even after adjusting
the parameters.

Action: No action required.

VDISK Version 2.0 Virtual Disk x

Explanation: VDISK. Issued when VDISK receives control
to install a virtual disk, and x tells you which drive letter is
being assigned to the virtual disk.

Action: No action required.

VERIFY is OFF | ON

Explanation: VERIFY. Informational message.
Action: No action required.
VM.TMP is an illegal file name and has been ignored

Explanation: LINK.VM.TMP cannot be used for an object
filename. Informational message that is meant as a a
warning.

Action: No action required.

Volume label (11 characters, ENTER for none) ?

Explanation: FORMAT. You are requested to enter a 1 to
1 1 character volume label that will be written on the disk
being formatted.

Action: If you do not want a volume label on the disk, press
only the ENTER key.

A-103

Warning! All data on non-removable disk drive x

will be lost

Proceed with Format (Y/N)?

Explanation: FORMAT. Prompt telling you that the fixed
disk will be formatted.

Action: If you do not want to format the fixed disk, type n.
If you want to format the fixed disk, type y.

Warning! Data in the DOS partition
could be DESTROYED. Do you wish to
continue ? [d]

Explanation: FDISK. The "Delete DOS Partition" option is
warning you that if you continue, all data in the DOS
partition on the current fixed disk could be destroyed.

Action: If you press Enter, the DOS partition will NOT be
destroyed. If you do wish to delete the DOS partition, type
Y and press Enter.

Warning-directory full
xxx file(s) recovered

Explanation: RECOVER. There is insufficient directory
space to recover more files.

Action: Copy some of the files to another disk, erase them
from this disk, and run RECOVER again.

Warning! Diskette is out of sequence
Replace the diskette or continue
Strike any key when ready

Explanation: RESTORE. The backup diskette is not the
next one in sequence.

A-104

Action: Replace the diskette unless you are sure no files on
the diskette(s) you skipped would be restored. RESTORE
will continue when you press a key. This message will be
repeated if you try to skip a diskette that contains part of a
file being restored.

Warning! File xx
is a read only file
Replace the file (Y/N)?

Explanation: RESTORE. The indicated file is read-only.

Action: Enter Y if you want to replace it or N if you do not.
RESTORE will continue after you press ENTER. You will
see this message only if you specified the /P option.

Warning! File xx

was changed after it was backed up

Replace the file (Y/N)?

Explanation: RESTORE. The indicated file on the fixed
disk has a later date and time than the corresponding file on
the backup diskette.

Action: Enter Y if you want to replace it with the backed up
version or N if you do not. RESTORE will continue after
you press ENTER. You will see this message only if you
specified the /P option.

Warning! Files in the target
root directory will be erased
Strike any key when ready

Explanation: RESTORE. This is a warning prompt to tell
you that the files in the root directory will be erased.

Action: If you do not want to proceed, press Ctrl-Break. To
continue, strike any key.

A- 105

Warning! No files were found to back up

Explanation: BACKUP. Informational message telling you
that no files were found to back up.

Action: No action required.

Warning! No files were found to restore

Explanation: RESTORE. No backup files were found that
matched the restore file specification.

Action: Make sure the criteria you specified for BACKUP is
what you want. Otherwise, this is an informational
message.

Warning: No stack segment

Explanation: LINK. Informational message. None of the
object modules specified contain a statement allocating
stack space.

Action: No action required.

Warning! Source is out of sequence
Replace source and or continue if okay
Strike any key when ready

Explanation: RESTORE. Informational prompt telling you
to that the source diskette is out of sequence.

Action: Replace the source diskette, and strike any key
when ready.

A-106

Warning! Target is Full

Explanation: BACKUP or RESTORE. The target device is
full. No more files can be restored.

Action: No action required.

Writing xxx bytes

Explanation: DEBUG. Informational message telling how
many bytes are being written.

Action: No action required.

x is not a choice. Enter a choice.

Explanation: FDISK. You entered x which is not a choice
for this question.

Action: Enter a valid choice.

x is not choice. Enter Y or "N"

Explanation: FDISK. You entered x which is not a choice
for this question.

Action: Enter Y or N.

xxxxxx is not a valid library

Explanation: LINK. The file specified as a library is invalid.
Action: No action required. Linker will abort.

A-107

xxxxxxxxxx bytes disk space freed

Explanation: CHKDSK. Informational message. Disk space
marked as allocated was not associated with a file. If you
used the /F parameter, the space was freed and made
available.

Action: No action required.

xxxx error on file yyyy

Explanation: PRINT. This message appears on the printer.
While attempting to read data from file yyyy for printing, a
disk error of type xxxx was encountered. Printing of that
file is stopped.

Action: Check that disk drive is ready.

xxx lost clusters found in yyy chains.
Convert lost chains to files (Y/N)?

Explanation: CHKDSK. Ctrl-Break was entered during a
disk I/O operation. CHKDSK did not clean up the disk
after encountering the Ctrl-Break.

Action: If you reply Y and you have used the /F parameter,
CHKDSK will recover each chain into a separate file,
otherwise, if you reply N, CHKDSK frees the blocks up so
they can be allocated to new files. If CHKDSK was
specified (no /F), then messages displayed afterwards are
informational (no corrective action was taken).

xxxxxx of xxxxxx bytes recovered

Explanation: RECOVER. This is an informative message
indicating the number of bytes of the specified file that were
recovered.

Action: No action required.

A-108

*** Files were backed up xx/xx/xxxx ***

Explanation: RESTORE. Informational message. The files
on the backup diskette were backed up on the indicated
date.

Action: No action required.

*** Restoring files from diskette xx ***

Explanation: RESTORE. Informational message. This
message is followed by a list of files that were restored from
the indicated diskette.

Action: No action required.
—More-
Explanation: MORE. The screen is full and there is more
data waiting to be displayed.

Action: Press any character to see the next full screen.
Numbers

10 Mismatches - ending compare

Explanation: COMP. Informational message. Ten
mismatched locations were detected in the files being
compared. COMP assumes that the files are so different
that further comparisons would serve no purpose.

Action: No action required.

A-109

Notes:

A-110

Index

Special Characters A

.-period 8-8,8-16
.COM file format 7-99
+ (plus sign)

in automatic response
file 9-21
$$$ - filename extension 8-5

EDLIN prompt 8-5, 8-10
global filename
character 2-8

* - EDLIN prompt 8-5, 8-10

* - global filename
character 2-8

- (DEBUG prompt) 10-14
/P parameter 7-79
/V parameter 7-61
/W parameter 7-79
/l parameter 7-90
/l parameter,

DISKCOMP 7-84
/8 parameter,

DISKCOMP 7-84
% (percent sign) 7-
? - global filename

character 2-7

* - pound sign 8-7
@ symbol (linker)
= equal sign 7-10

■28

A (Append Lines)

Command 8-11
A (Assemble)

Command 10-15
A> prompt 7-10
abort read/write

operation A-3
about messages 1-8
absolute sector 10-52
absolute segment address

how to determine 9-26
AC flag set condition 10-44
accessing a file 4-22
adding hexadecimal

values 10-30
address - DEBUG

parameter 10-6
address, disk transfer 10-5
analyze

diskettes 7-105
the directory 7-48
the File Allocation
Table 7-48
Append Lines command 8-11
applications,

random/sequential 4-8
ASCII characters 10-20
ASCII representation 10-5
ASCII values 10-11
Assemble Command 10-15
assembler 9-4
ASSIGN (Drive)

Command 7-14
ASSIGN drive command 7-14

Index- 1

Asynchronous

Communications

Adapter 7-132,7-137,7-138
ATTRIB (Attribute)

Command 7-17
ATTRIB command 7-17
AUTOEXEC.BAT file 7-27,

7-75
automatic program

execution 7-27
automatic response file

linker 9-21
AUX - reserved device

name 2-5
auxiliary carry flag 10-44
AX register 10-4

boundary, paragraph 9-6
boundary, 16-byte 10-20
boundary, 8-byte 10-20
BP register 10-4
brackets, square 7-10
BREAK (Control Break)

Command 7-43
BREAK Command 4-6,7-43
breakpoint 10-27
buffer, what is a 4-7
BUFFERS Command 4-7
BX register 10-4, 10-34
byte - DEBUG

parameter 10-7
byte contents

display 10-23

fill 10-26

replace 10-23

BACKUP Command 7-19
backup diskette 7-86
backup file, edit 8-5
BAK filename extension 8-6,

8-18, 8-27
BAT filename extension 7-24
Batch commands

ECHO 7-30

FOR 7-32

GOTO 7-33

IF 7-34

SHIFT 7-40
batch file 7-24, 7-38, 7-39,

7-180
Batch File Commands 7-24
batch file, using with
PATH 5-9

batch file, where DOS looks
for 5-15
batch processing 7-24
books, about DOS 1-3

C (Compare)

Command 10-19
C (Copy Lines)

Command 8-12
carry flag 10-44
change console, CTTY 7-72
change date 7-74
change diskettes 7-38
change filenames 7-156
change time 7-180
changing directories 5-7
changing the current

directory 5-14
CHDIR (Change Directory)

Command 7-45
CHDIR command 7-45
check for break 7-43
CHKDSK (Check Disk)

Command 7-48

Index-2

CHKDSK command 7-48
class 9-7

clear condition 10-43
clear screen 7-52
CLS (Clear Screen)

Command 7-52
codes, 8088 instruction 10-28
colon 7-10

color graphics adapter 7-113
Color/Graphics Monitor

Adapter 7-132
COM filename extension 7-8
comma 7-10
COMMAND (Secondary

Command Processor)

Command 7-53
COMMAND command 7-53
command line
linker 9-18
command parameters
DEBUG 10-6
EDLIN 8-7
command prompt,

DEBUG 10-13
command prompts, linker 9-8
COMMAND.COM 7-106,

10-4
commands

DEBUG 10-13
DOS 7-5
EDLIN 8-9
commands for directories 5-10
commands, end 7-11
commands, new 1-4
commands, summary of
commands, where DOS looks

for 5-15
Communications

Adapter 7-137
COMP (Compare Files)

Command 7-55
COMP command 7-55,7-86
Compare command 10-19

comparing diskettes 7-84
comparing files 7-55
comparing memory 10-19
compatibility,

DISKCOMP 7-88
compatibility,

DISKCOPY 7-94
compatibility, drives and

diskettes 1-7
computer, size of your 4-9
COMSPEC 7-165
COM1 - reserved device

name 2-5
CON - reserved name for

console/keyboard 2-5
concatenation 7-60, 7-67
CONFIG.SYS 4-3
Configuration Commands 4-5
BREAK 4-6
BUFFERS 4-7
COUNTRY 4-11
DEVICE 4-13
FCBS 4-19
FILES 4-22
LASTDRIVE 4-24
SHELL 4-25
console/keyboard 2-5
control keys 7-11, 8-9, 10-13
copy and combine files 7-67
COPY command 7-24,7-60,

7-86, 7-92
Copy Lines command 8-12
copy with different

filename 7-65
copy with same filename 7-63
copying diskettes 7-90
copying DOS to DOS

partition 3-22
copying files 7-60
copying your DOS

diskette 1-3, 7-162
country code 7-162
COUNTRY Command 4-11

Index-3

creating a .BAT file 7-28
creating a batch file 7-24
Creating a CONFIG.SYS

File 4-4
creating a new file 8-19
creating a subdirectory 5-11
CS register 10-4, 10-27,

10-29, 10-32, 10-50, 10-53
Ctrl-Break 9-8
Ctrl-Break keys 7-11,8-9,

8-16,8-19, 10-13
Ctrl-Num Lock keys 7-11, 8-9
Ctrl-NumLock keys 10-13
Ctrl-Zkeys 8-29
Ctrl-Break keys 7-38
Ctrl-Z character 7-68
Ctrl— PrtSc keys 7-185
CTTY (Change Console)

Command 7-72
CTTY command 7-72
current directory 5-6
current directory, changing or

displaying 5-14
CX register 10-4,10-5,10-34,

10-54
CY flag set condition 10-44

default 2-3

parameter 2-3
D (Delete Lines)
Command 8-13
D (Dump) Command 10-20
Date

change 7-74

enter 7-74
DATE Command 7-74
date format, select 7-162

DEBUG commands

A (Assemble) 10-15

C (Compare) 10-19

D (Dump) 10-20

E (Enter) 10-23

F (Fill) 10-26

G(Go) 10-27

H (Hexarithmetic) 10-30

I (Input) 10-31

L(Load) 10-32

M(Move) 10-35

N(Name) 10-36

O (Output) 10-38

P (Proceed) 10-39

Q (Quit) 10-40

R (Register) 10-41

S (Search) 10-46

T (Trace) 10-47

U (Unassemble) 10-49

W (Write) 10-52
DEBUG program

command parameters 10-6

commands 10-13

common information 10-13

ending 10-40

how to start 10-4

prompt 10-14

what it does 10-3
default disk transfer

address 10-5
default drive

linker 9-8

parameter 2-3
default segment 10-6
defective tracks 7-105
DEL (Delete) Command 7-77
DEL command 7-77
Delete Lines command 8-13
deleting a directory or
subdirectory 5-13
deleting a file 7-77
delimiters 7-11,8-9, 10-13
destination area 10-35

Index-4

DEVICE Command 4-13
device error messages A-4
device names, reserved 2-5,

7-11,7-65
device redirection 6-3
DGROUP 9-14
DI flag clear condition 10-44
DI register 10-4
DIR (Directory)

Command 7-79
DIR command 2-8,7-79,

7-108
direction flag 10-44
director, analyze 7-48
directories 5-3
directories, accessing 5-6
directories, levels 5-4
directory commands 5-10
directory entries 5-5
directory entries, listing 7-79
directory names 5-6
directory search, PATH 7-140
directory structure,

displaying 5-15
directory, current 5-6
directory, display 7-182
directory, displaying the

current 5-14
directory, how to organize 5-4
directory, make 7-130
directory, remove 7-161
disk transfer address 10-5
DISKCOMP (Compare

Diskettes Only)

Command 7-84
DISKCOMP command 7-84,

7-92
DISKCOMP

compatibility 7-88
DISKCOPY (Copy Diskettes

Only) Command 7-90
DISKCOPY command 7-84,

7-90

DISKCOPY

compatibility 7-94
diskette and drive
compatibility 1-7
diskette drives, types 1-6
diskette, naming 7-127
diskette, restore 7-157
diskettes

analyze 7-105

back up 7-86

change 7-38

comparing 7-84

copying 7-90

defective tracks 7-105

filenames 2-4

fragmented 7-92

initialize 7-105

preparing 7-105

recording format 7-105

status report 7-48
diskettes, types 1-6
display

byte contents 10-23

flags 10-42

lines 8-22

registers 10-42

remarks 7-39
display contents of

directory 7-182
display directory entries 7-79
Display DOS version

number 7-186
display instructions 10-49
displaying a file's
contents 7-185
displaying directory

structure 5-15
displaying memory 10-20
displaying the current

directory 5-14
DN flag set condition 10-44
DOS books 1-3

Index-5

DOS command, how to

enter 7-9
DOS commands

.bat 7-24

ASSIGN 7-14

ATTRIB 7-17

BACKUP 7-19

Batch processing 7-24

BREAK 4-6, 7-43

CHDIR 7-45

CHKDSK 7-48

CLS 7-52

COMMMAND 7-53

common information 7-10

COMP 7-55

COPY 7-60

CTTY 7-72

DATE 7-74

DEL 7-77

DIR 7-79

DISKCOMP 7-84

DISKCOPY 7-90

entering a DOS
command 7-9

ERASE 7-96

EXE2BIN 7-98

external 7-8

FDISK 7-101

FIND Filter 7-102

FORMAT 7-105

GRAFT ABL 7-113

GRAPHICS 7-115

internal 7-8

JOIN 7-118

KEYBxx 7-123

LABEL 7-127

MKDIR 7-130

MODE 7-132

MORE Filter 7-139

PATH 7-140

PAUSE 7-38

PRINT 7-143

PROMPT 7-149

RECOVER 7-153

REM 7-39

RENAME (or
REN) 7-156

RESTORE 7-157

RMDIR 7-161

SELECT 7-162

SET 7-164

SHARE 7-167

SHIFT 7-40

SORT Filter 7-169

SUBSTITUTE 7-172

SYS 7-178

TIME 7-180

TREE 7-182

TYPE 7-185

types of 7-8

VER 7-186

VERIFY 7-187

VOL 7-188
DOS device names 2-5
DOS diskette, about your 1-3
DOS diskette, copying 7-162
DOS diskette, using 1-3
DOS Editing Keys

entering DOS
commands 7-11

using DEBUG 10-13

using EDLIN 8-9
DOS files

displaying contents
of 7-185

fragmented 7-65

object 10-3

object program 7-185

source 8-3

text 7-185,8-3
DOS filters 6-7
DOS partition,

formatting 3-18
DOS version number,
display 7-186

Index-6

DOS, replacing previous

version 3-3
drive 2-3
drive - DEBUG

parameter 10-7
drive, assign new 7-14
DS register 10-4,10-5,10-23,

10-26, 10-35
/DSALLOCATION linker

parameter 9-14
dummy device 2-5
dummy parameters 7-28, 7-29
Dump command 10-20
DX register 10-4

E (End Edit) Command 8-18

E (Enter) Command 10-23

ECHO Subcommand 7-30

edit

backup file 8-5
existing file 8-5
partial file 8-11

Edit Line Command 8-16

editing a new file 8-6

editing keys 7-11,8-9, 10-13

EDLIN

A (Append Lines) 8-11
C (Copy Lines) 8-12
command parameters 8-7
commands 8-9
common information 8-9
creating a batch file 7-24
D (Delete Lines) 8-13
E (End Edit) 8-18
Edit Line 8-16
how to start 8-5
I (Insert Lines) 8-19
L (List Lines) 8-22

M (Move Lines) 8-25
P(Page) 8-26
program 8-3
prompt 8-5
Q (Quit Edit) 8-27
R (Replace Text) 8-28
S (Search Text) 8-31
T (Transfer Lines) 8-34
W (Write Lines) 8-35
EI flag set condition 10-44
End Edit command 8-6, 8-18
end-of-file 7-68
ending commands 7-11
Enter command 10-23
enter date 7-74
Enter key 2-5, 8-9
enter time 7-180
entering a DOS command 7-9
entries, directory 5-5
environment, set 7-164
equal sign ( = ) 7-10
ERASE Command 7-96
erasing a file 7-96
error message, device A-4
error messages A-3
error, recover from A-3
error, syntax 10-13
ES register 10-4, 10-5
Esc key 8-16
EXE filename extension 7-8,

9-10, 10-5, 10-34, 10-55
execute instructions 10-47
execute program 10-27
executing a .BAT file 7-29
executing files quickly 7-25
EXE2BIN Command 7-98
existing file, edit 8-5
ext 2-4
extension

.BAK 8-6,8-18,8-27
.COM 7-8

.EXE 7-8, 10-5, 10-34,
10-55

Index-7

.EXE filename
extension 9-10

.HEX 10-5, 10-34, 10-55

.MAP 9-11

.OBJ 9-9

5p5p5p 8-5
extensions 2-4
external commands 7-8

F (Fill) Command 10-26
FCB (see File Control Block)
FCBS (File Control Block)

Command 4-19
FDISK 3-6

change active
partition 3-13

create DOS partition 3-9

delete DOS partition 3-15

display partition
information 3-17

loading FDISK 3-7

next fixed disk 3-18

partitioning 3-4
FDISK Command 7-101
FDISK program, loading 3-7
FDISK, DOS partition 3-6
features, DOS 3.10 1-4
file attribute, read-only 7-17
File Control Block

(FCB) 10-36
file sharing 4-20,7-167
file specification 2-3
file, editing a new 8-6
filename characters, global 2-7
filename extensions

.BAK 8-6,8-18,8-27

.BAT 7-24

.COM 7-8

.EXE 7-8, 10-5, 10-34,
10-55

.EXE filename
extension 9-10

.HEX 10-5, 10-34, 10-55

.MAP 9-11

.OBJ 9-9

5p5p4> 8-5

characters, valid 2-4
filenames

length of 2-4

renaming 7-156
FILES Command 4-22
files, list all 7-81
files, list selected 7-82
files, number opened 4-23
filespec 2-3
filespec - DEBUG

parameter 10-7
Fill command 10-26
filter commands

FIND command 7-102

MORE command 7-139

SORT Command 7-169
filtering data 6-7
FIND Filter Command 7-102
First Asynchronous
Communications Adapter
port 2-5
fixed disk specifiers 3-4
fixed disk, formatting 3-18
fixed disk, partitioning 3-4
fixed disk, preparing your 3-4
fixed disk, restore 7-157
fixups, segment 7-99
flag values 10-41
flags 10-4
flags, display 10-42
FOR Subcommand 7-32
FORMAT Command 7-105
FORMAT compatiblity 7-110
FORMAT status report 7-109

Index-8

formatting, DOS
partition 3-18
fragmented diskettes 7-92
fragmented files 7-65
F3 key 10-32
F5 key 8-17
F6 key 2-5, 7-66, 8-29

HEX filename extension 10-5,

10-34, 10-55
Hexarithmetic

command 10-30
hidden files 7-50,7-108
HIGH 9-14

HIGH linker parameter 9-6
high memory 9-14,10-5

G (Go) Command 10-27
generating line numbers 8-3
global filename characters

* 2-7

? 2-7

examples using 2-9

in command name 7-11

in COPY 7-62

in DELETE. 7-78

inDIR 7-79

in ERASE 7-97

in RENAME 7-156
Go command 10-27,10-54
GOTO Subcommand 7-33
GRAFTABL (Load Graphics
Table) Command 7-113
GRAFTABL command 7-113
GRAPHICS (Screen Print)

Command 7-115
GRAPHICS command 7-115
group 9-7

H (Hexarithmetic)
Command 10-30

I (Input) Command 10-31

I (Insert Lines)
Command 8-19

IBMBIO.COM 7-79,7-106

IBMDOS.COM 7-79,7-106

IF Subcommand 7-34

initialize

diskettes 7-105

initializing the asynchronous
adapter 7-137

Input command 10-31

input file
linker 9-4

input files

Insert Lines command

insert mode 8-19

inserting lines 8-3

instruction codes, 8088

Instruction Pointer (IP)

instructions

display 10-49
execute 10-47
unassemble 10-49
variable length 10-49

internal commands 7-8

interrupt codes 10-28

interrupt flag 10-44

invoking a secondary
processor 7-53

8-19

10-28
10-4

Index-9

invoking one batch file from

another 7-25
IP (Instruction Pointer) 10-4
IP register 10-27, 10-41

JOIN Command 7-118

keyboard 2-5
keyboard code 7-162
keyboard layout, select 7-162
KEYBxx (Load Keyboard)

Command 7-123
KEYBxx Command 7-123
keys, control 7-11, 8-9, 10-13
keys, DOS editing 7-11, 8-9,

10-13

L (List Lines) Command 8-22
L (Load) Command 10-32
LABEL (Volume Label)

Command 7-127
LABEL command 7-127
LASTDRIVE Command 4-24
LINE 9-15

line - EDLIN parameter 8-7
Line Editor Program 8-3

line numbers 8-3

lines, renumber 8-13, 8-19

LINK

See linker(LINK) Program
linker files

automatic response 9-4,
9-21

input 9-4

library 9-4,9-12

listing 9-4, 9-10

object 9-4, 9-9

output 9-4

run 9-4, 9-10
linker parameters 9-14

/DS ALLOCATION 9-14

/HIGH 9-14

/LINE 9-15

/MAP 9-15

/PAUSE 9-15

/STACK 9-16
linker prompts 9-9
linker(LINK) Program

command line 9-18

command prompts 9-7

example session 9-23

messages 9-27

starting 9-17
list - DEBUG parameter 10-7
list all files 7-81
List Lines command 8-22
list selected files 7-82
listing data lines 8-26
listing directory entries 2-8,

7-79
Load command 10-32,10-54
load graphics table 7-113
load module 9-16,9-26
loading programs 7-98
loading standard device
drivers 4-13
loading, FDISK program 3-7

create DOS partition

Index-10

entire fixed disk for
DOS 3-9
part of fixed disk for
DOS 3-9
local v

LPT1 - reserved name for
printer 2-5

M (Move Lines)
Command 8-25
M (Move) Command 10-35
make directory, MKDIR 7-130
making a file read-only 7-17
making a subdirectory 5-11
/MAP linker parameter 9-15
MAP extension 9-11
memory

high 9-14, 10-5

low 9-14
memory status report 7-48
memory, loading files into 8-5
messages 1-8, A-3
messages, linker 9-27
MKDIR (Make Directory)

Command 7-130
MKDIR command 7-130
MODE Command 7-132
MORE Filter Command 7-139
Move command 10-35
Move Lines command 8-25

N (Name) Command 10-36
n - EDLIN parameter 8-8
NA flag clear condition 10-44
Name command 10-33,10-36
naming a diskette 7-127
NC flag set condition 10-44
new DOS commands 1-4
NG flag set condition 10-44
NUL: - reserved device
name 2-5
numbers, line 8-3, 8-13
NV flag clear condition 10-44
NZ flag clear condition 10-44

O (Output) Command 10-38
OBJ extension 9-9
object files 10-3
object modules 9-9
in response to linker
prompt 9-9
object program files 7-185
one-drive system 7-85, 7-92
operation, suspend

system 7-38
optional remarks, PAUSE

command 7-38
Output command 10-38
output files

linker 9-5
OV flag set condition 10-44
overflow flag 10-44

Index- 11

P (Page) Command 8-26
P (Proceed) Command 10-39
Page command 8-26
paragraph boundary 9-6
parallel printer to

Asynchronous

Communications

Adapter 7-138
parameter

DEBUG 10-6
dummy 7-28
EDLIN 8-7

testing with different 10-27
parameters, Linker 9-14
parity flag 10-44
partial file, edit 8-11
partition, FDISK 3-6
partitioning, fixed disk 3-4
path 5-6
PATH (Set Search Directory)

Command 7-140
PATH command 5-6,5-8,

7-140
path to a file 5-7
PATH, using in

AUTOEXEC.BAT 5-9
PAUSE 9-15, A-ll
PAUSE command 7-38
PC register 10-41
PE flag set condition 10-44
percent sign (%) 7-28
period (.) 8-8
period (.) 8-16
physical append 7-70
Piping standard I/O 6-6
piping, what is 6-6
PL flag clear condition 10-44
plus sign

in automatic response
file 9-21

PO flag clear condition 10-44
portaddress - DEBUG

parameter 10-8
pound sign (#) 8-7
prepare diskettes 7-105
preparing your fixed disk 3-4
print buffer size 7-143
PRINT Command 7-143
print device, specifying 7-143
print queue size 7-143
printer 2-5, 7-132
printing files 7-143
printing graphics 7-115
PRN - reserved name for

printer 2-5
Proceed command 10-39
program execution, stop 10-27
Program Segment Prefix 10-5
program, FDISK 3-6
prompt

DEBUG 10-14
EDLIN 8-5
PROMPT (Set System Prompt)

Command 7-149
PROMPT Command 7-149
protecting a file 7-17
protocol parameters 7-137
public symbols 9-25
punctuation 7-10

Q (Quit Edit) Command 8-27
Q (Quit) Command 10-40
questions mark 7-10
queue print files 7-143
Quit command 10-40
Quit Edit command 8-27
quotation marks 10-11

Index- 12

R (Register) Command 10-41
R (Replace Text)

Command 8-28
random/sequential

applications 4-8
range - DEBUG

parameter 10-8, 10-9
read-only 7-17
read/ write requests 4-8
read-only attribute 7-17
recording format,

diskette 7-105
RECOVER Command 7-153
recover from error A-3
redirection of I/O devices 6-3
Register command 10-41
registername - DEBUG

parameter 10-9
registernames, valid 10-41
registers, display 10-42
relative sector number 10-10
relative zero 9-25
relocatable loader 9-4
REM command 7-39
remarks, display 7-39
remarks, PAUSE

command 7-38
remote v
remove directory,

RMDIR 7-161
removing a directory 5-13
REN Command 7-156
RENAME (or REN)

Command 7-156
RENAME Command 7-156,

10-55
renumber lines 8-13, 8-19
replace byte contents 10-23
Replace Text command 8-28

replacing previous version of

DOS 3-3
reserved device names 2-5,

7-11,7-65
responses to the system A-3
RESTORE Command 7-157
retry read/write operation A-3
RMDIR (Remove Directory)

Command 7-161
RMDIR Command 7-161
root directory, getting back

to 5-7
run file 9-10

S (Search Text)

Command 8-31
S (Search) Command 10-46
saving diskette space 7-98
screen 2-5

screen print, graphics 7-115
screen, clear CLS 7-52
Search command 10-46
search directory, PATH 7-140
Search Text command 8-3 1
secondary command

processor 7-53
sector - DEBUG

parameter 10-10
sector number, relative 10-10
sector, absolute 10-52
sectors 7-92, 10-10
segment 9-6, 9-9
SEGMENT command 9-16
segment fixups 7-99
segment registers 10-4, 10-50
segment, default 10-6
segments, class 9-7
SELECT Command 7-162

Index- 13

SELECT procedure 1-3
select, date and time

format 7-162
select, keyboard layout 7-162
semicolon delimiter 7-10
SET (Set Environment)

Command 7-164
SET Command 7-164
set condition 10-43
set system prompt

command 7-149
SHARE Command 7-167
sharing, file 7-167
SHELL Command 4-25
SHIFT Subcommand 7-40
SI register 10-4
sign flag 10-44
slashes 7-10

SORT Filter Command 7-169
source area 10-35
source drive 7-10
source files 8-3
SP (Stack Pointer) 10-4
space delimiter 7-10
special characters 2-7
specifying a drive 2-3
specifying, print device 7-143
square brackets 7-10
SS register 10-4
stack allocation

statement 9-16
/STACK linker parameter
Stack Pointer (SP) 10-4
standard I/O device

redirection 6-3
standard I/O, piping 6-6
starting DEBUG 10-4
starting DOS from fixed

disk 3-23
starting EDLIN 8-5
starting the linker 9-17
status report 7-48
stop program execution 10-27

string - DEBUG

parameter 10-11
string - EDLIN parameter 8-8,

8-9
subdirectories 5-3
subdirectories, accessing 5-6
subdirectories, changing 5-6
subdirectory, creating a 5-11
SUBST 7-172
SUBST(Substitute)

Command 7-172
SUBSTITUTE

Command 7-172
summing files 7-70
suspend system operation 7-38
symbols, global and

public 9-15
syntax error 10-13
SYS (System)

Command 7-178
SYS Command 7-178
system configuration

commands 4-3
system devices 2-5
system files, transfer 7-178
system prompt 7-10
system prompt command,

set 7-149
system prompt, command is

complete 7-10

T (Trace) Command 10-47
T (Transfer Lines)
Command 8-34
target drive 7-12
temporary file, VM.TMP
terminate commands 7-11
text files 7-185,8-3

Index- 14

Time command 7-180

enter 7-180
time format, select 7-162
time, change 7-180
top-level command

processor 4-25
Trace command 10-47,10-54
tracks, defective 7-105
Transfer Lines command 8-34
transfer system files 7-178
TREE Command 7-182
tree-structure, displaying 5-15
tree-structured directories 5-3
TYPE Command 7-185
types of diskette drives 1-6
double sided

(320/360K) 1-6
high capacity ( 1 .2MB) 1 -6
single sided
(160/180K) 1-6
types of diskettes 1-6
double sided

(320/360K) 1-6
high capacity (1.2MB) 1-6
single sided
(160/180K) 1-6
types of DOS commands 7-8
typing the contents of a
file 7-185

UP flag clear condition 10-44

using applications v

using your DOS diskettes 1-3

value 10-12
variable length

instructions 10-49
VDISK.SYS 4-14

installing in config.sys 4-15
VER (Version)

Command 7-186
VER Command 7-186
VERIFY Command 7-187
virtual disk 4-14
VM.TMP temporary files
VOL (Volume)

Command 7-188
VOLUME Command 7-188
volume label 7-127

U (Unassemble)

Command 10-49
Unassemble command 10-49
unassemble instructions 10-49
unprintable characters 10-20

W (Write Lines)

Command 8-35
W (Write) Command 10-52
where DOS looks for

commands and batch

files 5-15
Write command 10-52
Write Lines command 8-35

Index- 15

zero flag 10-44

ZR flag set condition 10-44

Index- 16

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