Sabre 850 problems on Suns

[Carlo Kopp]

I am looking for advice on the configuration of the CDC Sabre 850 when run
with  a Xylogics 753 or 7053 installed on a Sun 3 or 4 running 4.0.3 or
4.1.

We have had an interesting situation with a customer site  (4/260 4.0.3
7053)  which  reported  continuing problems with its 850s, these devices
were repeatedly replaced and the problems still recurred. Finally, we
installed one of the 'suspect' 850s on a Solbourne 4/602 4.0D with a 753
and ran it, much to our surprise it performed flawlessly.

When we installed the drive on a 3/160 running 4.1 with a 753 it failed
almost immediately with assorted media errors, returned to the Solbourne
it again performed flawlessly.

We suspect that the problem arises due to some aspect of the drive's
behaviour not agreeing with Sun's implementation of the 7053/753 SMD
driver, probably as a result of the drive being configured in a way which
falls outside of the 'envelope' of workable Sabre/753/driver
configurations.

Does anybody have any material which documents the limitations of the
driver used, and also does anybody have a set of known reliably working
configurations for the Sabre under these conditions (ie drive switch
settings and format parameters)?

I would be grateful for any advice on this matter (Sun's are not my daily
occupation) and I am quite happy to publish a summary of the results once
this is resolved.

carlo at gaia.gcs.oz.au (Carlo Kopp, Solbourne Computer Australia)