The MS-DOS Encyclopedia
The MS-DOS Encyclopedia is the most comprehensive reference work
available on Microsoft's industry-standard operating system. Written
for experienced microcomputer users and programmers, it contains
detailed, version-specific information on all the MS-DOS commands,
utilities, and system calls, plus articles by recognized experts in
specialized areas of MS-DOS programming. This wealth of material is
organized into major topic areas, each with a format suited to its
content. Special typographic conventions are also used to clarify the
Organization of the Book
The MS-DOS Encyclopedia is organized into five major sections, plus
appendixes. Each section has a unique internal organization;
explanatory introductions are included where appropriate.
Section I, The Development of MS-DOS, presents the history of
Microsoft's standardsetting operating system from its immediate
predecessors through version 3.2. Numerous photographs, anecdotes, and
quotations are included.
Section II, Programming in the MS-DOS Environment, is divided into
five parts: Structure of MS-DOS, Programming for MS-DOS, Customizing
MS-DOS, Directions of MS-DOS, and Programming Tools. Each part
contains several articles by acknowledged experts on these topics. The
articles include numerous figures, tables, and programming examples
that provide detail about the subject.
Section III, User Commands, presents all the MS-DOS internal and
external commands in alphabetic order, including ANSI.SYS, BATCH,
CONFIG.SYS, DRIVER.SYS, EDLIN, RAMDRIVE.SYS, and VDISK.SYS. Each
command is presented in a structure that allows the experienced user
to quickly review syntax and restrictions on variables; the
less-experienced user can refer to the detailed discussion of the
command and its uses.
Section IV, Programming Utilities, uses the same format as the User
Commands section to present the Microsoft programming aids, including
the DEBUG, SYMDEB, and CodeView debuggers. Although some of these
utilities are supplied only with Microsoft language products and are
not included on the MS-DOS system or supplemental disks, their use is
intrinsic to programming for MS-DOS, and they are therefore included
to create a comprehensive reference.
Section V, System Calls, documents Interrupts 20H through 27H and
Interrupt 2FH. The Interrupt 21H functions are listed in individual
entries. This section, like the User Commands and Programming
Utilities sections, presents a quick review of usage for the
experienced user and also provides extensive notes for the less-
The 15 appendixes provide quick-reference materials, including a
summary of MS-DOS version 3.3, the segmented (new) .EXE file header
format, an object file dump utility, and the Intel hexadecimal object
file format. Much of this material is organized into tables or
bulleted lists for ease of use.
The book includes two indexes--one organized by subject and one
organized by command name or system-call number. The subject index
provides comprehensive references to the indexed topic; the command
index references only the major entry for the command or system call.
The MS-DOS Encyclopedia contains numerous program listings in assembly
language, C, and QuickBASIC, all designed to run on the IBM PC family
and compatibles. Most of these programs are complete utilities; some
are routines that can be incorporated into functioning programs.
Vertical ellipses are often used to indicate where additional code
would be supplied by the user to create a more functional program. All
program listings are heavily commented and are essentially self-
The programs were tested using the Microsoft Macro Assembler (MASM)
version 4.0, the Microsoft C Compiler version 4.0, or the Microsoft
QuickBASIC Compiler version 2.0.
The functional programs and larger routines are also available on
disk. Instructions for ordering are on the page preceding this
introduction and on the mail-in card bound into this volume.
Typography and Terminology
Because The MS-DOS Encyclopedia was designed for an advanced audience,
the reader generally will be familiar with the notation and
typographic conventions used in this volume. However, for ease of use,
a few special conventions should be noted.
Capital letters are used for MS-DOS internal and external commands in
text and syntax lines. Capital letters are also used for filenames in
Italic font indicates user-supplied variable names, procedure names in
text, parameters whose values are to be supplied by the user, reserved
words in the C programming language, messages and return values in
text, and, occasionally, emphasis.
A typographic distinction is made between lowercase l and the numeral
1 in both text and program listings.
Cross-references appear in the form SECTION NAME: PART NAME,
COMMAND NAME, OR INTERRUPT NUMBER: Article Name or Function
Color indicates user input and program examples.
Although not an official IBM name, the term PC-DOS in this book means
the IBM implementation of MS-DOS. If PC-DOS is referenced and the
information differs from that for the related MS-DOS version, the
PC-DOS version number is included. To avoid confusion, the term DOS is
never used without a modifier.
The names of special function keys are spelled as they are shown on
the IBM PC keyboard. In particular, the execute key is called Enter,
not Return. When <Enter> is included in a user-entry line, the user is
to press the Enter key at the end of the line.
The common key combinations, such as Ctrl-C and Ctrl-Z, appear in this
form when the actual key to be pressed is being discussed but are
written as Control-C, Control-Z, and so forth when the resulting code
is the true reference. Thus, an article might reference the Control-C
handler but state that it is activated when the user presses Ctrl-C.
Unless specifically indicated, hexadecimal numbers are used
throughout. These numbers are always followed by the designation H (h
in the code portions of program listings). Ranges of hexadecimal
values are indicated with a dash--for example, 07-0AH.
In the printed version of the book, the notation (more) appears
in italic at the bottom of program listings and tables that
are continued on the next page. The complete caption or table title
appears on the first page of a continued element and is designated
Continued on subsequent pages.
Book Design by The NBBJ Group, Seattle, Washington
Cover Design by Greg Hickman
Principal Typography by Carol L. Luke
The manuscript for this book was prepared and submitted to Microsoft
Press in electronic form. Text files were processed and formatted
using Microsoft Word.
Text composition by Microsoft Press in Garamond with display in
Garamond Bold using the Magna composition system and the Linotronic
300 laser imagesetter.
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