Problems with 2 UDA50's on a Vax 750

[Peter Gross]

We have a 750 with two unibuses, each with a UDA50 and RA81.
Originally, 4.1 wouldn't work with two unibuses, but after applying
some fixes I got from Steve Haflich at MIT, I had no problems using the
second unibus.  We have a DR11-W there interfaced to a Grinnell Frame
Buffer, and have had no problems using it.  The 2nd UDA50, however,
doesn't work, hanging during the udopen() routine.  The process is
sleeping with priority -25, and of course can't be killed.  The fault
led's on the UDA50 have a 2 in them, which the UDA50 User Guide says is
"microcode stuck in init step 2", most likely failure being M7161 or
M7485 or SOFTWARE.  I am pretty convinced it is software.  There were
lots of hardware problems with this UDA, but DEC got everything fixed
up, and it passes diagnostics now with flying colors.  We are at a loss
of what to do, having no programming documentation at all on the
UDA50.  Has anyone ever hooked up two UDA50's on either a 750 or a 780
under 4.1? I would even like to hear from people running multiple
RA81's on one UDA50.

--peter gross
seismo!hao!pag
decvax!kpno!hao!pag
(303)-494-5151 ext. 348

PS.  Here is the fragment from my config file dealing with the UDA50 and
     RA81's:
controller	uba0	at nexus ?
controller	uba1	at nexus ?
controller	uda0	at uba0 csr 0172150		vector udintr
disk		ra0	at uda0 drive 0
controller	uda1	at uba1 csr 0172150		vector udintr
disk		ra1	at uda1 drive 0

I made special device files for the 2nd RA81 to have minor dev numbers
starting at 8.