Third Party Disks for 4D/25

[Dave Olson]

ian at dgp.toronto.edu (Ian S. Small) writes:

>A word of warning re third party disks - what works now may not
>work tomorrow.  We have been running Wren V's on both Personal Irises
>and Power Irises without too much distress after some initial teething
>problems.

>One of the Personal Iris/Wren V combinations just upgraded to 3.2 and
>guess what?  His Wren V doesn't behave any more.  SGI's response appears
>to be:  "We didn't support it, it's your problem."  We have only tried to
>upgrade the one machine, so cannot determine if this problem is endemic
>across the entire line, or whether it is just Personal Irises, or
>just 4D/25's for that matter.

As I have replied to many people privately, we discovered the hard
way that CDC made some mistakes in the firmware on the Wren IV, V,
VI, and possibly VII SCSI drives.  It was first discovered (by us)
on the Wren VI 760 Mb drive; after we discovered it, it showed
up in new releases of firmware for the IV and V models.  If you
are experiencing SCSI bus timeouts, this is almost certainly the
problem.  Contact your vendor to get your DRIVE firmware upgraded.
CDC has released new firmware that resolves the problem for all
the drives listed above.

The 3.2 release supports synchronous SCSI if the drive also supports it
(on the 4D/20 and 4D/25 only).  All the Wren V drives do support it.
On the 4D25 in particular, we have a very high transfer rate.
This exposed the bugs in the CDC firmware.  If you want to mail
me which Wren V you have, and it's firmware rev (boot the system
with bootmode set to d, or use the 'ide' program), I can try
(unofficially) to determine if you have the faulty firmware.

I would like to hear just who it was at SGI that gave you the
reply you indicated above.  Our support people generally contact
me when SCSI issues arise, and I haven't had your problem referred
to me.  I'm posting this reply rather than mailing, specifically
to let people know that we DO try to support our customers,
even when unsupported hardware is used (as far as is reasonable, of
course).  Particularly in cases like this, where there is a
known problem, we can try to help.  Issues like this are one of
the reasons why supported hardware costs more when purchased
from a systems vendor; we DO support it with extensive, and
continuing, testing and qualification work.
	Dave Olson

It's important to keep an open mind, but not so open
that your brains fall out. -- Stephen A. Kallis, Jr.