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From: Terry Lambert <terry@lambert.org>
Message-Id: <199607102112.OAA27270@phaeton.artisoft.com>
Subject: Re: bootable CD's (fwd)
To: joerg_wunsch@uriah.heep.sax.de
Date: Wed, 10 Jul 1996 14:12:26 -0700 (MST)
Cc: freebsd-hackers@freebsd.org, jleppek@suw2k.hisd.harris.com
In-Reply-To: <199607101822.UAA10672@uriah.heep.sax.de> from "J Wunsch" at Jul 10, 96 08:22:43 pm
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> > If anyone comes up with any pointers I am willing to give it a try, I am
> > also trying to get the info from gigabyte.
> 
> What magic do you expect?
> 
> I don't know, but i would blindly assume that booting the CD will be
> done in the same way as booting any other device.  The BIOS code
> searches all available devices, and tries to load the very first
> sector onto address 0:0x7c00.  If the loaded sector ends in 0x55aa, it
> will simply be executed.  It's up to the executed code to decide what
> needs to be done next.  That's why you could put a boot-selector MBR
> there, or you could put the 7.5 KB BSD bootstrap there as well.
> 
> CD-ROM sectors are 2 KB, not only 512 bytes, but who says you cannot
> examine the very first 512 bytes only?

Read the Joliet specification from Microsoft.

I expect that the Adaptec boot code conforms to this specification.

Conforming boot code will read the first sector from the first
*session* of a multisession CD, rather than the first sector from
the CD itself.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.