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From: Jon Moldenhauer <jpm@almond.elite.net>
Message-Id: <199704080535.WAA20719@almond.elite.net>
Subject: BIOS reports geometry wrong, help.
To: freebsd-hackers@freebsd.org
Date: Mon, 7 Apr 1997 22:35:40 -0700 (PDT)
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A machine I have has a 'strange' problem: the BIOS is
reporting totally incorrect geometry to the bootloader
and the result is the bootloader crashes on a divide
by zero error.  This applies only to the hard disk
drives in the machine.

After tinkering with the boot block code and trying 
various things out, I narrowed down the problem to be
an invalid geometry returned from interrupt 0x13,
subfunction 0x8 in the bios.S function get_diskinfo()
(the geometry being returned is 1023 cylinders, 256
heads, 0 sectors).

If anyone else has seen this, I would be interested in
any suggestions you might have for fixing it.  It is
possible to hardwire the drive's geometry into the boot
block, but I would like to stay away from that
alternative.

Thanks,

Jonathon
jpm@elite.net