Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!att!cbnewsc!psfales
From: psfales@cbnewsc.att.com (Peter Fales)
Newsgroups: comp.os.msdos.programmer
Subject: Re: DOS in ROM?
Message-ID: <1990Oct7.165800.29216@cbnewsc.att.com>
Date: 7 Oct 90 16:58:00 GMT
References: <687@aio.jsc.nasa.gov>
Organization: AT&T Bell Laboratories
Lines: 32

In article <687@aio.jsc.nasa.gov>, poirot@aio.jsc.nasa.gov (Daniel Poirot) writes:
> Several of the manufacturors of EPROM boards for the PC advertise the
> capability of running DOS in ROM.  I am interested in a copy of the ROM
> image if one is available.
> 
> Has anyone had any experience with putting DOS in ROM?  I understand
> Radio Shack, Grid and Digital Research all use some sort of DOS in
> ROM.

I have been experimenting recently with putting DOS in ROM in order to
improve the performance of my floppy disk only laptop machine (a
Sharp PC-4501).  After disassembling a few key parts of the boot sector
and IO.SYS, it did not turn out to be too difficult.  

The laptop BIOS helped out quite a bit by treating the ROM card as 
a third floppy device.  Creating the ROM image was just a matter of
putting DOS, COMMAND.COM, CONFIG.SYS, AUTOEXEC.BAT, and all my standard
utilities on a floppy disk, then simply copying that disk image byte 
for byte into a series of EPROMS.  I did have to patch a few bytes
to get the system to boot from a floppy drive other than A:, but it
seems to be working quite well.

I would be interested in knowing the ROM cards for standard PCs work.
I can't imagine how one would boot from the ROM card without creating
a new BIOS or BIOS extensions.  Once booted an installable device
driver could get access to the ROM device.

-- 
Peter Fales			AT&T, Room 5B-420
N9IYJ            		2000 N. Naperville Rd.
UUCP:	...att!ihlpb!psfales	Naperville, IL 60566
Domain: psfales@ihlpb.att.com	work:	(708) 979-8031