kdq@demott.COM (Kevin D. Quitt) (09/19/90)
I am looking for someone who is *very* familiar with the bootstrap
process of MSDOS, especially the initial operation of IO.SYS.
Situation is as follows:
Logical Design PC Clone is sitting on the VME BUS, with 64K of shared
dual-ported RAM and 16 mailbox registers. A SYSV UNIX system is running
a device that responds to requests generated by the PC, via interrupt, data
in the mailboxes and data in the RAM itself.
The goal is to allow the PC to boot off of the UNIX disk, from a
file which will be an image of a DOS disk. The contents of the file
includes the standard bootstrap, FATs, dir, and the three system files.
The disk is identified as a floppy that has 1 head, 16 sectors per
track, and 512 tracks.
We steal int 13h when the int 18H is taken, and trap all requests for
drive a: to go over the membrane (shared RAM).
The BIOS code works, the data is transmitted across the membrane
properly, it pulls in the boot sector, the root dir, IO.SYS, starts IO.SYS,
reads in the FAT, then goes out to lunch.
If you are *really* a guru, I am willing to pay for your services.
Sorry if this violates nettiquette, but on Monday I am likely to turn
into a toad - and that makes it hard to type. An ICE will arrive Thursday,
but I'm not convinced that will help a whole lot.
--
_
Kevin D. Quitt demott!kdq kdq@demott.com
DeMott Electronics Co. 14707 Keswick St. Van Nuys, CA 91405-1266
VOICE (818) 988-4975 FAX (818) 997-1190 MODEM (818) 997-4496 PEP last
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