This is more of a warning message than a question, perhaps.
I recently did an update of one of my Alphastation 255 systems from
Digital UNIX 4.0B to 4.0D. The disks in this system were Quantum
Fireball TM3200S (both system and user data).
The upgrade went without incident, but ever since then, the machine
would run normally for between 10 and 60 minutes, then hang completely.
Messages about i/o errors (deferring i/o on all available scsi devices)
appeared on the console. Shutdown was impossible, the only recourse was
the halt button.
It seems likely to me that the Quantum disks are to blame (especially
having transferred the system to a couple of Seagate drives, and it now
operating normally). This same model of drive behaved in almost exactly
the same way to me about a year ago, when fitted in a VAXstation 4000/90
(OpenVMS 6.2). That is, it would work just well enough to act as a
write-only medium - long enough to put data on it before hanging the
system!
The final answer is in dejanews somewhere under comp.os.vms, but if I
remember rightly, the Quantum drives don't perform command tag queuing
properly. I assume that the SCSI drivers in Unix 4.0D have been enhanced
to use this feature, with the consequence that the Quantum drives are no
longer safe to use. If, indeed, they ever were. I doubt I will ever use
a Quantum drive in anything fancier than a Mac in future.
Graham
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Received on Wed Mar 25 1998 - 18:51:56 NZST