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From: braun@m10ux.UUCP (MHx7079 mh)
Newsgroups: comp.sys.ibm.pc
Subject: ROM on expansion boards
Message-ID: <209@m10ux.UUCP>
Date: Mon, 8-Jun-87 14:08:36 EDT
Article-I.D.: m10ux.209
Posted: Mon Jun  8 14:08:36 1987
Date-Received: Fri, 12-Jun-87 01:19:21 EDT
References: <3661@osu-eddie.UUCP>
Organization: AT&T Bell Labs, Murray Hill
Lines: 29
Summary: How are they formatted?

I plugged an Ampex Megastore host adapter card into a PC 6300.
This board is mostly latches and gates, and 4k of ROM, located
at C800:0000.  When the machine is booted, the diagnostics recognize
the existance of the ROM, and apparently call some initialization
code on it (which announces an error, but that's another story).

I am trying to disassemble/debug the code in this ROM, and I need to know:

How does the system recognize the existance of the ROM?
I have already heard of (and verified) the ROM checksum.

What format does the ROM have so the system can call initialization
code on it?  I assume the purpose of this code is to initialize the card
and then overlay some interrupt vectors for hard disk I/O.

What is the BIOS support for hard disks?  (I have DOS 2.11)
This board is part of a hard disk system, but it does not at all
resemble the standard IBM controller.
What interrupts relate to hard disks?

What is a good book for arcane hardware questions like these?


I remain, etc.,

-- 

Doug Braun		AT+T Bell Labs, Murray Hill, NJ
m10ux!braun		201 582-7039