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Date: Thu, 6 Jun 1996 09:35:41 -0700 (PDT)
From: Michael Dillon <michael@memra.com>
To: hdalog@zipnet.net
cc: dror@hopf.dnai.com, freebsd-scsi@freebsd.org, freebsd-isp@freebsd.org
Subject: Re: ERROR info:747d9d asc:11,0 Unrecovered read error, other SCSI issues
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Message-ID: <Pine.BSI.3.93.960606092829.11961K-100000@sidhe.memra.com>
Organization: Memra Software Inc. - Internet consulting
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On Thu, 6 Jun 1996, Peter Dufault wrote:

> 3. dd from /dev/zero to that partition.  The write will force the sector
> to remap;

If you are talking about the internal SCSI remapping, then when the
internally allocated table is full, no more remapping will take place
resulting in error reports by the OS. Generally a drive with that many
errors can be replaced under warranty.

I remember the older 1 gig Quantum drives that would not work in *ANY*
UNIX system. I had one drive in BSDI system reporting lots of errors. Ran
diagnostics and it was clean. Put it into a Linux machine, still lots of
errors, diagnostics report was clean. Different host adapter. Same
problem. Put in a Windows workstation and it works like a charm.

A month later while setting up a SCO UNIX box, we got wierd, wierd read
errors. They weren't reported in the system log, but a database program
was definitely getting the wrong data off the drive. It was the same
Quantum 1 gig drive so we sent it back, grabbed two 500 meg IDE's off the
shelf and everything works now.

Maybe Quantum's engineering does something wierd internally and doesn't
test their drives on a real world activity mix that includes UNIX. 


Michael Dillon                                   ISP & Internet Consulting
Memra Software Inc.                                 Fax: +1-604-546-3049
http://www.memra.com                             E-mail: michael@memra.com