Microsoft Windows 98 Second Edition README for MS-DOS Config.sys Commands April 1999 
	
(c) Copyright Microsoft Corporation, 1999 

This document provides complementary or late-breaking information to supplement the Microsoft Windows 98 Second Edition 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 Second Edition 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. 
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 in MS-DOS 6.x, 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 is used only in conjunction with the /L switch and affects only UMBs for which a minimum size is 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 30. 

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.) Suppressing 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. 
You can find more information on MS-DOS commands on your Windows 98 Second Edition CD-ROM. Open the file \Windows 98\tools\oldmsdos\help.com.