Newsgroups: comp.sys.apollo
Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!alchemy.chem.utoronto.ca!system
From: system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson))
Subject: CRC Errors on DN10K disks
Message-ID: <1990Aug10.165408.6894@alchemy.chem.utoronto.ca>
Keywords: Disk errors, 760MB Maxtor disks
Organization: University of Toronto Chemistry Department
References: <9008101419.AA02633@pan.ssec.honeywell.com>
Date: Fri, 10 Aug 90 16:54:08 GMT

In article <9008101419.AA02633@pan.ssec.honeywell.com> thompson@PAN.SSEC.HONEYWELL.COM (John Thompson) writes:
> ...
>We have also had some difficulties with disk errors that are reported as :
>    8:59:21 pm (CDT)  disk error
>      Winchester  Ctrl_# = 0  Unit_# = 1    Phys daddr = 45C3: disk operation \
>                  completed successfully after crc correction (OS/disk manager)
>      Above disk chains a multiple-disk group - actual error is on:
>      Winchester  Ctrl_# = 1  Unit_# = 1    Phys daddr RELATIVE to this drive...
>This is the same as someone reported earlier.  We have been told that this
>problem MAY be because "HP tests there disks more rigorously, and marginal
>ones aren't installed."  Unfortunately, we have gotten a (smaller) number of
>the same error from the original Apollo disk that was there.  Our guess is
>that the power supply, which has some bricks that were manufactured during
>a dubious time period (failures have been attributed to bricks made during
>this time) is not giving out enough juice to lay down a reliable format on
>the INVOL.  After we get a new supply, we're going to re-format the disks
>and monitor the problem.

Our DN10020 has 4 760 MB disks, and we get one of these messages every 2
days on average (but they tend to come in clumps), and are concentrated on 2
of the 4 disks. They have appeared mainly since SR10.2.p, but that may
be a coincidence, since 3 of our 4 disks were replaced not long before
SR10.2.p was installed (we had 3 head crashes in 2 weeks).
I would be very interested to hear if replacing the power supply does
fix this, as our power supply board was replaced recently (it kept
turning off the power, so it may have been acting up when those 3 disks
were invol'ed).
-- 
Mike Peterson, System Administrator, U/Toronto Department of Chemistry
E-mail: system@alchemy.chem.utoronto.ca
Tel: (416) 978-7094                  Fax: (416) 978-8775