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From: "John S. Dyson" <toor@dyson.iquest.net>
Message-Id: <199603251315.IAA25614@dyson.iquest.net>
Subject: Re: Adaptec 1542B and 1522 on current kernels
To: syssgm@devetir.qld.gov.au (Stephen McKay)
Date: Mon, 25 Mar 1996 08:15:59 -0500 (EST)
Cc: gibbs@freefall.freebsd.org, freebsd-current@freebsd.org,
        syssgm@devetir.qld.gov.au
In-Reply-To: <199603250750.RAA25263@orion.devetir.qld.gov.au> from "Stephen McKay" at Mar 25, 96 05:50:52 pm
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> 
> My problem turned up after an upgrade (amongst other things) of my processor
> from a 486DX33 to a 486DX4/100.  I run FreeBSD 2.0.5 on it.  I got lots of
> sd0: timed out and MBO was 01 should be 00.  My solution was to attempt to
> avoid immediate reuse of mailboxes, based on a theory of how my BT545S could
> be postponing mailbox updates when it was really busy.  The MBO problems
> disappeared, but the timeouts remained.
> 
Certainly not to dispute problems that some people have been having, but
using the bt driver with the BT545S, I had *extremely* stable SCSI subsystem
operation.  My machine was a 486/66 non-write back (early CPU.)  I wonder
if some MBs don't support cache invalidation properly?

John