Disk Operating System (DOS)
Starting and customizing the MS-DOS Mode in MS-Windows 98 through MS-Windows XP.
MS-DOS Mode in Win98-WinXP
Starting the MS-DOS Mode in Windows
MS-DOS Mode is not like the DOS session which runs inside of Window's protected-mode GUI, it is DOS in Real Mode. It is does not support for long file names, multitasking, or protected mode drivers.
Starting MS-DOS Mode
Since there are no protected-mode device drivers in MS-DOS mode, you must load real-mode drivers for any devices that you want to use, including CD-ROM and mouse.
If you are starting the MS-DOS Mode via an exit to DOS PIF, real-mode drivers must be loaded via the customized AUTOEXEC and CONFIG.SYS settings specified in the Advanced tab of the PIF.
(If you are booting directly to DOS drivers are loaded from either CONFIG.SYS or AUTOEXEC.BAT).
Customizing MS-DOS Mode
In the Advanced Tab of DOS PIF properties, place a check in the
MS-DOS Mode check box. This makes available the following selections:
When MS-DOS Mode is run, Windows renames the existing CONFIG.SYS to CONFIG.WOS and AUTOEXEC.BAT to AUTOEXEC.WOS.
Bruce Miller, 2002, 2014