<operating system> A text file containing special system configuration commands, found in the root directory on an MS-DOS computer, typically on drive C (the hard disk). It is read by MS-DOS at boot time, after the setup has been read from CMOS RAM and before running AUTOEXEC.BAT. It can be modified by the user.
Some example commands which CONFIG.SYS might contain are:
DEVICE=C:\DOS\HIMEM.SYS /testmem:offLoad the extended memory manager.
DEVICE=C:\DOS\EMM386.EXE RAMLoad the expanded memory manager.
BUFFERS=10,0Specify memory for disk buffers.
FILES=70Set the number of files that can be open at once.
DOS=UMBDOS is located in UppeMemoryBlock.
LASTDRIVE=ZDisk drives are A: to Z:.
FCBS=16,0Set the number of file control blocks.
DEVICEHIGH /L:1,12048 =C:\DOS\SETVER.EXEReport the DOS version to older programs.
DOS=HIGHDOS should maintain a link to UMB.
COUNTRY=358,437 C:\DOS\COUNTRY.SYSSet the country code for some programs.
STACKS=9,256Set dynamic stacks for hardware control.
SHELL=C:\DOS\COMMAND.COM C:\DOS\ /E:1024 /pSet the location of the command interpreter.