Re:
> We replaced a CPU card on 918. This was pre-configured for HP-UX. We changed
> it to MPE through ss-config and did a fresh installation on the system (SLT
> tape of MPE/iX 5.5)

Hmm...that's a *LOT* more work than necessary when simply changing a CPU card!

I'd expect you to adequately backup the machine, power it off,
pull the old card, plug in the new card, and start it up ... having HP
reconfigure the card if necessary (e.g., if your HP CE brought in a CPU
card from an HP 9000 instead of an HP 3000).

But...you're reloading?

What are you omitting?  Are you changing from a 9x7 or 9x2 or 9x5 to
the 9x8 at the same time?  (That would explain the problem you encountered.)

If you try to boot with a system I/O configuration that is incorrect, it isn't
uncommon to end up with just ldev 1 and 20!  If, for example, you used an SLT
from a 917, and tried to boot to the CONFIG group from that tape, then
MPE would be unable to access any devices because their configured I/O
paths would be missing the "56/" portion.  Note: MPE makes 1 and 20
work for you, luckily.

> The H/W config is :
>
> Disk : 56/52.6.0
> DDS Tape Drive : 56/52.0.0
> CD-ROM Drive    : 56/52.2.0


> Also we get "Pascal error -650" when system comes up.

My first guess here is that you're booting up with MPE/iX 5.0 or earlier.
There's a Y2K bug in the predictive support software (that starts at bootup),
which results in several errors at bootup.   (IIRC)

Stan Sieler                                           [log in to unmask]
www.allegro.com/sieler/wanted/index.html          www.allegro.com/sieler