Microsoft KB Archive/39877

No Release of ROMable MS-DOS Available PSS ID Number: Q39877 Article last modified on 02-23-1993 PSS database name: O_MSDOS

2.x 3.x 4.00 4.01

MS-DOS

Question:

Does Microsoft make a version of MS-DOS that is ROMable (i.e., stored and run from the ROM BIOS of a system, instead of being stored on a disk)? If so, how can I obtain it?

Response:

There is currently no release of MS-DOS that runs from ROM. An OEM (original equipment manufacturer) would have to license the MS-DOS OEM BAK (Binary Adaptation Kit) to attempt this. A few OEMs have done this, normally for their laptop computer systems.

The “normal” ROM start-up looks for a disk and loads the boot sector, which starts a sequence of events that loads MS-DOS from the disk.

Most OEMs that have modified MS-DOS to work from ROM have not made a “true” ROM version of MS-DOS. They have usually modified their ROM start-up routine to take the portion of MS-DOS stored in ROM and copy it to RAM and then simulate a boot. (A “true” ROM release of MS-DOS would not need to be copied into RAM during the ROM start-up procedure.)

Additional reference words: 2.x 3.x 4.00 4.01 noupd

Copyright Microsoft Corporation 1993.