[Spock@SAMSON.cadr.dialnet.symbolics.com: IFU]

[Barry Margolin <barmar@THINK.COM>]

We've had LOTS of problems getting reliable IFUs and XSQs.  We started
having trouble with one of our 3645s this summer (generally, crashes
were the only symptom).  We replaced both boards several times, and
continued to have problems.  We downgraded the machine to a 3640 while
our CE tried to find us a working board set.  He kept ordering new sets,
and he would run them in his test system for several days.  It took him
over a month to get a set that worked reliably.

A common problem with these, according to our CE, is getting a set of
boards that work well together.  At the parts depot they do some testing
of the boards, but on an individual board basis, not as whole sets.
Sometimes different boards have slightly different tolerances, so an IFU
that worked in the depot's test system might not work in your system.

Our CE has also complained that the DOA rate of IFUs is around 75%.

Unfortunately, the performance benefits of a working IFU seem to justify
the difficulty of getting one.

                                                barmar