From owner-freebsd-scsi  Fri Oct 12 17:45:52 2001
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To: David Greenman <dg@root.com>
Cc: Alexey Koptsevich <alex@astro.su.se>, scsi@freebsd.org
Subject: Re: Adaptec 3210S: RAID5 performance and bus throughput 
In-Reply-To: Message from David Greenman <dg@root.com> 
   of "Fri, 12 Oct 2001 16:53:18 PDT." <20011012165318.C18001@nexus.root.com> 
Date: Fri, 12 Oct 2001 17:53:23 -0700
From: Mike Smith <msmith@freebsd.org>
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>    You only need to do two reads, one from the disk you are updating and one
> from the disk that has the parity. When you XOR the old data from the parity
> data, you've removed it and can XOR in the new data. Two reads, two writes.

Blah.  I knew my numbers looked wrong, but I was busy trying to make the
other point (you don't have to read the stripe) and instead made a fool
of myself.

Oh well.  I only write device drivers anyway. 8)

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