Autoexec.bat and config.sys help and instructions

Autoexec.bat and config.sys information


Computer Hope

The autoexec.bat and the config.sys were files created for MS-DOS and Windows three.x to load device and operating system files to properly run. These files are required for later revisions of MS-DOS and Windows three.x to load. However, with newer versions of Windows are no longer needed.

How to edit the files

The auotexec.bat and the config.sys are edited past the MS-DOS command file edit. To edit these files, blazon
edit c:\autoexec.bat
to edit the autoexec.bat file, or
edit c:\config.sys
to edit the config.sys file. If the mouse drivers are not loaded properly, the mouse will non piece of work.

If y’all have Windows 95, Windows 98, or Windows ME, we recommend you use the sysedit command. To run sysedit, click Start, Run, and type


Windows XP and afterwards no longer employ the autoexec.bat or config.sys file.

Remarking lines in the autoexec.bat or the config.sys allows you to temporarily or permanently prevent a line from loading each time y’all boot the computer. To remark a line, type
in front of each line you want to skip.


If you get errors with an autoexec.bat line, remark the line instead of removing the line, in instance it needs to be added once again.

Getting boosted memory

The following commands help your computer load programs into memory more efficiently, allowing y’all to have more memory for MS-DOS programs and games.

Make sure y’all take the three lines beneath at the offset of your config.sys file.


By placing the
on the second line, this tin save memory because it’south loading DOS into upper retentivity earlier loading the memory manager. Additionally, the first and tertiary lines cannot be loaded into high memory because these lines are the memory managers.

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Load all your devices in the config.sys and autoexec.bat into loftier memory.

Autoexec.bat layout

Beneath is an case of how the autoexec.bat may look.

@echo off
Set Audio=C:\PROGRA~1\Creative\CTSND
Gear up Blaster=A220 I5 D1 H5 P330 E620 T6
Set PATH=C:\Windows;C:\

The following is some of the more common lines found in the autoexec.bat and further data virtually each of the lines.

@repeat off

Tells MS-DOS to read the lines just not echo them or their results back to the screen.


The set audio is telling the computer to send all sound events that the computer may run to that directory containing the sound drivers.

Ready BLASTER=A220 I5 D1 H5 P330 E620 T6

Tells the reckoner to prepare the Sound Blaster settings, which is a good line for estimator games or other programs needing sound. If you accept this line in your autoexec.bat, you have all settings for your audio carte du jour. A220 is a port accost of 220, I5 is IRQ v, and D1 is DMA 1. These settings are the typical settings for most audio cards.

Fix PATH=C:\Windows;C:\

Sets the reckoner path to look in the C:\Windows directory or the root if a command used at the prompt is not institute.

LH C:\Windows\Command\MSCDEX.EXE /D:123

A line used to load the CD-ROM into the high retentiveness surface area. If you have Windows 95+, the MSCDEX is in the C:\Windows\Control directory. In Windows 3.x or DOS, this file is in either in C:\DOS or C:\Windows directory. The /D:123 is the name of the driver name that loads in upper memory; this can be anything, usually /D:MSCD0001. Proceed in mind that this is non the driver, information technology is the name of the driver. If y’all modify this line, it needs to likewise be changed in the config.sys on your CD-ROM line. If the ii are not the same, your CD-ROM drive will non load.

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Loads the mouse driver into loftier retentiveness. Still, non all mice use the same drivers. Although the mouse may utilize mouse.exe, it could also be “” or “mouse.sys,” loaded in the config.sys.


Loads the smartdrive disk cache utility into retentivity. Run into the smartdrv command page for additional information about this utility.


Load doskey into retention so it can be accessed from the control line.


Run the cls MS-DOS control to clear screen.


Used for users using Windows 3.x, this line loads automatically Windows when booting the reckoner. Without this control the computer would simply load to the MS-DOS prompt.

Config.sys layout

Below is an example of how the config.sys may wait.


The following is some of the more mutual lines establish in the config.sys file and farther information about each of the lines.


The himem.sys line is an important line; this line allows you to load drivers into high retentiveness area. If this line is not present, Windows 3.x will not load.


Load DOS into high memory in an upper memory block.


This line should be placed later on the himem.sys.


The EMM386 line loads the extended memory manager. Yet, some older MS-DOS games have problems with extended retention and will not run without the NOEMS statement.


The files line allow Windows to load xxx files at the same time. However, going higher may subtract the figurer’southward functioning; 30 is found to work the best. Also, make sure the line is one line and that there’s not a space between and after the = (equal sign).

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The stacks line was offset used in MS-DOS 3.2 and was used to swap the stack whenever an asynchronous hardware interrupt occurred. Later in MS-DOS 3.three the line STACKS=0,0 was added into the config.sys. In special circumstances, this line was changed to STACKS=nine,128.

The STACKS statement has a range of 8-64, 32-512. If a higher value is entered, you volition receive a “FATAL: Internal stack failure, system halted mistake.”


Buffers line is to load buffers into retentivity allowing Windows to load memory.


The ansi.sys line is a commuter for DOS to allow you to have dissimilar colors and sizes and special characters at the DOS prompt.


The CD-ROM drivers for the CD-ROM drive. The /D:123 represents the proper name of the driver, which is named 123, however, can exist named anything, usually MSCD0001. However, keep in listen that the /D:123 must be the aforementioned in config.sys and autoexec.bat. If they are dissimilar, the CD-ROM will not work in MS-DOS.


Allows you to specify the last drive installed on the computer. It is non recommended this line exist used unless you are using Windows 3.11 or earlier since later on version of Windows ignore this line.


A line used to specify the number of file control blocks for file sharing. Should but be used when programs require it, and today, is non used or required. FCBS tin utilize between one and 255.

Technical support

  • How to fix the bad command or file name boot fault.
  • Himem.sys missing or corrupt.
  • How to fix MS-DOS issues with Windows ME.
  • How to get sound in MS-DOS.
  • How to fix Stack overflow system halted error.
  • How to get the mouse to work in MS-DOS.
  • Batch file aid and support.
  • MS-DOS and Windows control line help and support.