From owner-freebsd-scsi  Sat Jul 27 08:14:33 1996
Return-Path: owner-freebsd-scsi
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id IAA13081
          for freebsd-scsi-outgoing; Sat, 27 Jul 1996 08:14:33 -0700 (PDT)
Received: (from grog@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id IAA13074;
          Sat, 27 Jul 1996 08:14:30 -0700 (PDT)
From: Greg Lehey <grog>
Message-Id: <199607271514.IAA13074@freefall.freebsd.org>
Subject: Re: Setting disk sector size?
To: julian@whistle.com (Julian Elischer)
Date: Sat, 27 Jul 1996 08:14:30 -0700 (PDT)
Cc: scsi
In-Reply-To: <199607270213.TAA24690@shrimp.whistle.com> from "Julian Elischer" at Jul 26, 96 07:13:49 pm
X-Mailer: ELM [version 2.4 PL24]
Content-Type: text
Sender: owner-freebsd-scsi@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

> > A friend of mine just turned up with a Tandem disk drive (looks for
> > all the world like an IBM :-) which has 514 byte sectors.  He also has
> > another one with 516 byte sectors.  By all accounts we can change that
> > to 512 with 'scsi -m 3 -p 3 -e', except that the driver gets all
> > uptight about the 514 byte sectors and doesn't get as far as reading
> > the mode page.  scsiformat can report the format, so there must be
> > some way to do read the information, and I suspect there's also a way
> > to set it.  Does anybody have any ideas?
> 
>  compile a krnrel without that test in sd.c
> and use that to change the setup..
> > 

I tried that before I sent the message.  It hangs (OK, to be more
specific, it times out).  I think that the problem is that scsi tries
to access the disk before it reads the mode page.  scsiformat issues a
direct scsi command, so I assume that I could issue a write command
and write it back.  Unfortunately, I'm on vacation at the moment, and
I don't have any documentation with me.

Greg