Need help with Ultrix 1.2 driver bug

[Allan G. Weber]

Does anybody know of a reason for a device driver that works fine on a
VAX running 4.2BSD or Ultrix 1.1, not running on Ultrix 1.2?

I have an image processing peripheral (a Trapix 55/256C, by Recognition
Concepts Inc.) that is causing all sorts of headaches.  The device connects
to the hardware via a Q-bus interface.  For the last year, we had it
connected to a VAX 11/750 running 4.2BSD using a Able Qniverter
Unibus-to-QBus adapter.  It ran fine the whole time.  We recently removed
the Qniverter and connected the device to the Q-Bus of a VaxStation-II
running Ultrix 1.2.

After installing the driver, it appeared to work fine for awhile.  However
whenever somebody is using the device, the system crashes at random times.
I haven't been able to determine any pattern of commands to the device that
causes the crashes.  Sometimes everything just stops and other times we get
a console messages about "panic trap: reserved operand" or something like
that.  If the device is not being used, the system runs fine.

One thing I have noticed that is now different than when the device was on
the 750 has to do with powering up the device.  On the 750, if the device
was powered up and somebody tried to access it before running the program
that initialized it, the software returned error messages.  On the
VaxStation, doing the same thing causes the system to crash every time.  It
would appear that maybe the Unibus/Qniverter/4.2 combo was more forgiving
than the current configuration towards something that may have been
happening all the time.

The company that wrote the driver has only tried it on a MicroVax-II running
Ultrix 1.1 and they have seen nothing like this happen on their system.
They supplied the driver only in binary form, but I have dis-assembled and
dis-complied it back into C so I can try some experiments and changes if
anybody has any suggestions.

Any help would be greatly appreciated.  Thank you.

				Allan Weber
				USC Signal and Image Processing Institute
				Weber%Brand at USC-ECL.ARPA
				...sdcrdcf!usc-oberon!brand!weber
				(213) 743-5519