From owner-freebsd-hackers  Sun Mar 16 18:16:10 1997
Return-Path: <owner-hackers>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id SAA12969
          for hackers-outgoing; Sun, 16 Mar 1997 18:16:10 -0800 (PST)
Received: from seagull.rtd.com (seagull.rtd.com [198.102.68.2])
          by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id SAA12950
          for <freebsd-hackers@freefall.FreeBSD.org>; Sun, 16 Mar 1997 18:16:02 -0800 (PST)
Received: (from dgy@localhost) by seagull.rtd.com (8.7.5/8.7.3) id TAA16102 for freebsd-hackers@freefall.cdrom.com; Sun, 16 Mar 1997 19:15:28 -0700 (MST)
From: Don Yuniskis <dgy@rtd.com>
Message-Id: <199703170215.TAA16102@seagull.rtd.com>
Subject: Re: wd driver questions 
To: freebsd-hackers@freefall.FreeBSD.org (FreeBSD hackers)
Date: Sun, 16 Mar 1997 19:15:27 -0700 (MST)
X-Mailer: ELM [version 2.4 PL24]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

It seems that Terry Lambert said:
> 
> > >> And, how (if at all) does the geometry written to the disklabel
> > >> figure into the operation/calculations of the driver?
> > >
> > >As far as I could decipher from the driver code (wd.c) the probed geometry
> > >is used only to read the label.
> > 
> > No, the probed geometry is used for everything in the driver.
> 
> Why are we using a probed geometry insted of the geometry reported
> from the INT 0x13 call in the boot blocks?  The idea that the drive
> could be INIT'ed to a different geometry is valid.

This is the heart of the "problem" that I was discussing.  My disks,
for example, are INITed by the system ROMs to a particular geometry.
*Then* the probe (actually, the attach()) queries the drive
and reINITs the drive for the *default* drive geometry (which, in
my case, is very different from the "BIOS" geometry.

See my followup (long) post on this...
--don