[comp.os.msdos.programmer] rom bios extensions

kjh@pollux.usc.edu (Kenneth J. Hendrickson) (08/25/90)

I have an application that I'd like to put on a rom, and have recognized
as a rom bios extension at boot up time by the existing rom bios.

I know this is possible, but I don't know the correct format for the rom
bios extension.  I know that the first two bytes must be 55 AA, and that
there is some information as to how long the rom bios extension is, and
that there is some kind of checksumming.

Can anybody provide more information?  Can anybody tell me where to
look for more information?  Please reply by email, and I will summarize
to comp.sys.ibm.pc.

By the way, the book "The NEW Peter Norton's Guide to the IBM PC & PS/2"
mentions the existance of rom bios extensions, but GIVES NO FURTHER
DETAILS.  I consider this a SERIOUS OMMISION, and I hope it will be
remedied in the next edition of this otherwise acceptable book.

-- 
Ken Hendrickson N8DGN/6       kjh@usc.edu      ...!uunet!usc!pollux!kjh