Summary
This article contains a copy of the information in the Config.txt file included with Windows 98. This file is located in the Windows folder after you install Windows 98.
More Information
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Microsoft Windows 98 README for
MS-DOS Config.sys Commands
April 1998
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(c) Copyright Microsoft Corporation, 1998
This document provides complementary or late-breaking
information to supplement the Microsoft Windows 98
documentation.
------------------------
How to Use This Document
------------------------
To view Config.txt on-screen in Notepad, maximize
the Notepad window.
To print Config.txt, open the file in Notepad or
another word processor, then on the File menu, click Print.
In syntax lines, lowercase text signifies replaceable
parameters and uppercase text must be typed as it appears.
NOTE: The Msdosdrv.txt file contains more Help for
MS-DOS commands. Also you can type the name of the
command at the command prompt, followed by a slash
and question mark (/?). For example: CHKDSK /?
If you have the Windows 98 CD, you can get additional
help on MS-DOS commands, including syntax and examples.
You can load the MS-DOS 6 help file by browsing the
\tools\oldmsdos menu, and then clicking Help.com.
--------
CONTENTS
--------
ACCDATE
BREAK
BUFFERS/BUFFERSHIGH
DEVICE
DEVICEHIGH
DOS
DRIVPARM
FCBS/FCBSHIGH
FILES/FILESHIGH
INSTALL/INSTALLHIGH
LASTDRIVE/LASTDRIVEHIGH
NUMLOCK
REM
SET
SHELL
STACKS/STACKSHIGH
SWITCHES
-------------------------------
ACCDATE
=======
For each hard disk, this command specifies
whether to record the date that files are
last accessed. Last access dates are turned
off for all drives when your computer is
started in safe mode, and are not maintained
on floppy disks by default.
Syntax
ACCDATE=drive1+|- [drive2+|-]...
Parameters
drive1, drive 2...
Specifies the drive letter.
+|-
Specify a plus sign (+) to indicate that
the last access date should be maintained
for files on the drive. Specify a minus
sign (-) to indicate that the last access
date should not be maintained for files.
BREAK
=====
This command sets or clears extended CTRL+C
checking. You can use this command at the
command prompt or in your CONFIG.SYS file.
You can press CTRL+C to stop a program or an
activity, such as file sorting. Typically, MS-DOS
checks for CTRL+C only while it reads from the
keyboard or writes to the screen or a printer. If
you set BREAK to ON, you extend CTRL+C checking to
other functions, such as disk read and write
operations.
Syntax
BREAK [ON|OFF]
To display the current BREAK setting at the command
prompt, use the following syntax:
BREAK
In your CONFIG.SYS file, use the following syntax:
BREAK=ON|OFF
Parameter
ON|OFF
Turns extended CTRL+C checking on or off.
BUFFERS/BUFFERSHIGH
===================
This command allocates memory for a specified number
of disk buffers when your system starts. Use the
BUFFERSHIGH command to load the buffers in the upper
memory area. You can use these commands only in your
Config.sys file.
Syntax
BUFFERS=n[,m]
BUFFERSHIGH=n[,m]
Parameters
n
Specifies the number of disk buffers. The value of
n must be in the range 1 through 99. The default
is 30.
m
Specifies the number of buffers in the secondary
buffer cache. The value of m must be in the range
0 through 8. The default is 0 (no secondary cache
buffers).
If you specify an invalid value for n or m, BUFFERs uses
the default settings.
DEVICE
======
This command loads into memory the device driver you
specify. You can use this command only in your Config.sys
file.
Syntax
DEVICE=[drive:][path]filename [dd-parameters]
Parameters
[drive:][path]filename
Specifies the location and name of the device driver
you want to load.
[dd-parameters]
Specifies any command-line information required by
the device driver.
DEVICEHIGH
==========
This command loads the device driver you specify into
the upper memory area. Loading a device driver into the
upper memory area frees more bytes of conventional memory
for other programs. If upper memory is not available,
the DEVICEHIGH command functions just like the DEVICE
command.
You can use this command only in your Config.sys file.
Syntax
DEVICEHIGH [drive:][path]filename [dd-parameters]
To specify the region(s) of memory into which to
load the device driver, use the following syntax:
DEVICEHIGH [[/L:region1[,minsize1][;region2[,minsize2] [/S]]=
[drive:][path]filename [dd-parameters]
Parameters
[drive:][path]filename
Specifies the location and name of the device
driver you want to load into the upper memory area.
dd-parameters
Specifies any command-line information required by
the device driver.
Switches
/L:region1[,minsize1][;region2[,minsize2]...
Specifies one or more regions of memory into which
the device driver is loaded. By default, MS-DOS loads
the driver into the largest free upper memory block
(UMB) and makes all other UMBs available for the driver's
use. You can use the /L switch to load the device driver
into a specific region of memory or to specify which
region(s) the driver can use.
To load the driver into the largest block in a
specific region of upper memory, specify the region
number after the /L switch. For example, to load the
driver into the largest free block in region 4, you
would type /L:4. To list the free areas of memory,
type MEM /F at the command prompt.
When loaded with the /L switch, a device driver
can use only the specified memory region. Some
device drivers use more than one area of memory;
for those drivers, you can specify more than one
region. To find out how a particular device driver
uses memory, issue the MEM /M command and specify
the device-driver name as an argument. To specify
two or more regions, separate the block numbers
with a semicolon (;). For example, to use blocks
2 and 3, you would type /L:2;3.
Typically, MS-DOS loads a driver into a UMB in
the specified region only if that region contains
a UMB larger than the driver's load size (usually
equal to the size of the executable program file).
If the driver requires more memory while running
than it does when loaded, you can use the minsize
parameter to ensure that the driver will not be
loaded into a UMB that is too small for it. If you
specify a value for minsize, MS-DOS loads the driver
into that region only if it contains a UMB that is
larger than both the driver's load size and the
minsize value.
/S
Shrinks the UMB to its minimum size while the
driver is loading. Using this switch makes the
most efficient use of memory. This switch is
generally used only by the MemMaker program,
which can analyze a device driver's memory use
to determine whether the /S switch can safely be
used when loading that driver. This switch can
be used only in conjunction with the /L switch
and affects only UMBs for which a minimum size
was specified.
DOS
====
This command specifies that MS-DOS should maintain a link
to the upper memory area, load part of itself into the high
memory area (HMA), or both. You can use this command only in
your Config.sys file.
Syntax
DOS=HIGH|LOW[,UMB|,NOUMB][,AUTO|,NOAUTO]
DOS=[HIGH,|LOW,]UMB|NOUMB[,AUTO|,NOAUTO]
DOS=[HIGH,|LOW,][UMB,|NOUMB,]AUTO|NOAUTO
Parameters
UMB|NOUMB
Specifies whether MS-DOS should manage upper
memory blocks (UMBs) created by a UMB provider
such as Emm386.exe. The UMB parameter specifies
that MS-DOS should manage UMBs, if they exist.
The NOUMB parameter specifies that MS-DOS should
not manage UMBs. The default setting is NOUMB.
HIGH|LOW
Specifies whether MS-DOS should attempt to load
a part of itself into the HMA (HIGH) or keep all
of MS-DOS in conventional memory (LOW). The default
setting is LOW.
AUTO|NOAUTO
Specifies whether MS-DOS should automatically load
Himem.sys, Ifshlp.sys, Dblbuff.sys, and Setver.exe
device drivers if they are not explicitly loaded in
your Config.sys file. The default setting, AUTO,
automatically loads these device drivers. The AUTO
setting also automatically uses the BUFFERSHIGH,
FILESHIGH, FCBSHIGH, LASTDRIVEHIGH, and STACKSHIGH
commands, whether the -HIGH form of the command is
used or not. If you specify the NOAUTO parameter, you
must load these device drivers and use the -HIGH form of
the above commands in order to take advantage of them.
DRIVPARM
========
This command defines parameters for devices such as disk and
tape drives when you start MS-DOS. You can use this command
only in your Config.sys file.
The DRIVPARM command modifies the parameters of
an existing physical drive. It does not create a new
logical drive. The settings specified in the
DRIVPARM command override the driver definitions
for any previous block device.
Syntax
DRIVPARM=/D:number [/C] [/F:factor] [/H:heads] [/I] [/N]
[/S:sectors] [/T:tracks]
Switches
/D:number
Specifies the physical drive number. Values for number
must be in the range 0 through 255. For example, drive
number 0 = drive A, 1 = drive B, 2 = drive C, and so on.
/C
Specifies that the drive can detect whether the drive
door is closed.
/F:factor
Specifies the drive type. The following table shows the
valid values for factor and a brief description of each.
The default value is 2.
0 160K/180K or 320K/360K
1 1.2 megabyte (MB)
2 720K (3.5-inch disk)
5 Hard disk
6 Tape
7 1.44 MB (3.5-inch disk)
8 Read/write optical disk
9 2.88 MB (3.5-inch disk)
/H:heads
Specifies the maximum number of heads. Values for
heads must be in the range 1 through 99. The default
value depends on the value you specify for /F:factor.
/I
Specifies an electronically compatible 3.5-inch
floppy disk drive. Use the /I switch if your
computer's ROM BIOS does not support 3.5-inch
floppy disk drives.
/N
Specifies a nonremovable block device.
/S:sectors
Specifies the number of sectors per track that
the block device supports. Values for sectors
must be in the range 1 through 99. The default
value depends on the value you specify for /F:factor.
/T:tracks
Specifies the number of tracks per side that the
block device supports. The default value depends on
the value you specify for /F:factor.
FCBS/FCBSHIGH
=============
This command specifies the number of file control blocks (FCBs)
that MS-DOS can have open at the same time. Use the FCBSHIGH
command to load the FCBs in the upper memory area. You can use
these commands only in your Config.sys file.
Syntax
FCBS=x
FCBSHIGH=x
Parameter
x
Specifies the number of file control blocks that
MS-DOS can have open at one time. Valid values for
x are in the range 1 through 255. The default
value is 4.
FILES/FILESHIGH
===============
This command specifies the number of files that MS-DOS can
access at one time. Use the FILESHIGH command to load the
command in the upper memory area. You can use these commands
only in your Config.sys file.
Syntax
FILES=x
FILESHIGH=x
Parameter
x
Specifies the number of files that MS-DOS can
access at one time. Valid values for x are in
the range 8 through 255. The default value is 8.
INSTALL/INSTALLHIGH
===================
This command loads a memory-resident program into memory
when you start MS-DOS. Use the INSTALLHIGH command
to load the memory-resident program into the upper
memory area. You can use these commands only in
your Config.sys file.
Memory-resident programs stay in memory as long
as your computer is on. They can be used even when
other programs are active. You can use the INSTALL
or INSTALLHIGH command to load MS-DOS memory-resident
programs.
Syntax
INSTALL=[drive:][path]filename [command-parameters]
INSTALLHIGH=[drive:][path]filename [command-parameters]
Parameters
[drive:][path]filename
Specifies the location and name of the
memory-resident program you want to run.
command-parameters
Specifies parameters for the program you
specify for filename.
LASTDRIVE/LASTDRIVEHIGH
=======================
This command specifies the maximum number of drives you can
access. Use the LASTDRIVEHIGH command to load the LASTDRIVE
data structures in the upper memory area. You can use these
commands only in your Config.sys file.
The value you specify represents the last
valid drive that MS-DOS is to recognize.
Syntax
LASTDRIVE=x
LASTDRIVEHIGH=x
Parameter
x
Specifies a drive letter in the range A through Z.
NUMLOCK
========
This command specifies whether the NUM LOCK key is set to ON or
OFF when your computer starts. You can use this command only in
your Config.sys file.
Syntax
NUMLOCK=[ON|OFF]
Parameters
ON|OFF
If set to ON, turns on the NUM LOCK key when MS-DOS
displays the startup menu. If set to OFF, turns
NUM LOCK off.
REM
===
This command enables you to include comments in a batch file or
in your Config.sys file. The REM command is also useful for
disabling commands. You can use a semicolon (;) instead of the
REM command in your Config.sys file, but not in batch files.
Syntax
REM [string]
Parameters
string
Specifies any string of characters, for example,
the command you want to disable or the comment
you want to include.
SET
===
This command displays, sets, or removes MS-DOS environment
variables.
You use environment variables to control the
behavior of some batch files and programs and to
control the way MS-DOS appears and works. The SET
command is often used in the Autoexec.bat or
Config.sys files to set environment variables each
time you start MS-DOS.
Syntax
SET variable=[string]
To display the current environment settings at
the command prompt, use the following syntax:
SET
Parameters
variable
Specifies the variable you want to set or modify.
string
Specifies the string you want to associate
with the specified variable.
SHELL
=====
This command specifies the name and location of the command
interpreter you want MS-DOS to use. You can use this command
only in your Config.sys file.
If you want to use your own command interpreter instead of
Command.com, you can specify its name by adding a SHELL
command to your Config.sys file.
Syntax
SHELL=[[drive:]path]filename [parameters]
Parameters
[[drive:]path]filename
Specifies the location and name of the command
interpreter you want MS-DOS to use.
parameters
Specifies any command-line parameters or switches
that can be used with the specified command interpreter.
STACKS/STACKSHIGH
=================
This command supports the dynamic use of data stacks to handle
hardware interrupts. Use the STACKSHIGH command to load the
stacks in the upper memory area. You can use these commands
only in your Config.sys file.
Syntax
STACKS=n,s
STACKSHIGH=n,s
Parameters
n
Specifies the number of stacks. Valid values for
n are 0 and numbers in the range 8 through 64.
s
Specifies the size (in bytes) of each stack.
Valid values for s are 0 and numbers in the range
32 through 512.
SWITCHES
=========
This command specifies special options in MS-DOS. Use this
command only in your Config.sys file.
Syntax
SWITCHES= /F /K /N /E[:n]
Switches
/K
Forces an enhanced keyboard to behave like a
conventional keyboard.
/N
Prevents you from using the F5 or F8 key to bypass
startup commands. (SWITCHES /N does not prevent you
from pressing CTRL+F5 or CTRL+F8 to bypass Drvspace.bin
or Dblspace.bin; to prevent this, use the D**SPACE /SWITCHES
command to add the SWITCHES /N setting to your
D**space.ini file.)
/E[:n]
Used without the :n parameter, indicates that
Io.sys should suppress the automatic relocation
of EBIOS. (Automatic relocation of EBIOS
increases the conventional memory available to
MS-DOS-based programs.) Supressing automatic
relocation results in less conventional memory
available to MS-DOS-based programs. Use the /E
switch with the n parameter to relocate N bytes
of EBIOS to low memory, where n is the number of
bytes to be relocated. The minimum value for n
is 48 and the maximum value is 1024. The number
specified is always rounded up to the next multiple
of 16.