Using Batch Files to Start with Different Configurations (74995)

The information in this article applies to:
    Microsoft MS-DOS operating system 3.1
    Microsoft MS-DOS operating system 3.2
    Microsoft MS-DOS operating system 3.21
    Microsoft MS-DOS operating system 3.3
    Microsoft MS-DOS operating system 3.3a
    Microsoft MS-DOS operating system 4.0
    Microsoft MS-DOS operating system 4.01
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a

This article was previously published under Q74995


Some programs that access extended memory through their own methods may not run if HIMEM.SYS is installed the CONFIG.SYS file. These programs generally have the number 386 in the title (for example, AutoCAD 386). To run these programs, you will need to restart your computer with a different CONFIG.SYS file each time you want to run a different conflicting application/environment. You can do this process manually each time, or you can use batch files and a small executable program to restart your machine.

NOTE: If you are using MS-DOS 6.0 or later, you can use multiple configuration menus or the CHOICE.COM program to configure your system. For more information on using these options under MS-DOS 6.0 or later, type HELP MULTI-CONFIG or HELP CHOICE at the MS-DOS command prompt and then press ENTER.


To create the files to automatically restart your computer with the appropriate configuration, do the following:

Create a directory on your hard drive called C:\CONFIGS. Create the CONFIG.SYS and AUTOEXEC.BAT files you need to boot your system for HIMEM.SYS and applications that require it, with the following names:
Create the CONFIG.SYS and AUTOEXEC.BAT files you need to start your system for the program that conflicts with HIMEM.SYS. Any unique file extension can be used. The following example uses 386:
The following DEBUG script can be used to create a small executable file called REBOOT.COM. This file, when executed, will cause your system to restart. To create the file, change to the DOS directory, and type the following:


Enter the following information, pressing ENTER key after each line:
A 100                     ; Debug instruction for assemble
MOV AH,0D                 ; Disk Reset

INT 21h                   ; causes SmartDrv 4.x to write cache

MOV AX, 40                ; set up segment addressing
OR  BYTE PTR    [17],0C   ; equivalent of pressing CTRL+ALT
MOV AX,4F53               ; Issue a "DEL" (53h = DEL scan code)

INT 15h                   ; EMM386 sees this & shuts down.

MOV WORD PTR [72],1234    ; Set REBOOT flag to Warm-Boot (0=cold)
JMP F000:FFF0             ; Execute the internal restart routine
<CR>                      ; This line must be blank (just hit ENTER)
20                        ; File size to be written to disk (in hex)
N REBOOT.COM              ; Filename
W                         ; Write the file to disk
Q                         ; Quit Debug
NOTE: The REBOOT.COM file created with this debug script is compatible with SMARTDrive and its write-behind cache feature. The instructions in REBOOT.COM cause SMARTDrive to write (flush) its write-behind cache to disk before the computer is rebooted.

The following commands can be used to copy and rename the configuration files to the root directory of the C drive and restart the computer. To simplify the process, you can put these commands into batch files.

To start your machine for Windows, use the following commands:
   copy c:\configs\autoexec.dos c:\autoexec.bat
   copy c:\configs\config.dos c:\config.sys
To start your machine for the 386 application, use the following commands:
   copy c:\configs\autoexec.386 c:\autoexec.bat
   copy c:\configs\config.386 c:\config.sys

Modification Type: Major Last Reviewed: 11/26/2003
Keywords: KB74995