yechiel@aecom.UUCP (Yechiel Corn) (09/22/84)
We are planning to run 4.2 on an 11/750. We want to equip it with
an RA-80 with UDA-50 controller, TU-80 tape drive, 1 DZ, and an Able DH/DM.
Is it possible/advisable to put all this on one UBA? There are enough
backplane slots; this is not the issue. DEC has a
UDA-50 driver for Sys V, and it specifies that it requires its own UBA.
They say its because the UDA-50 uses up too many Address Map Registers
on the Unibus and as a result, the kernel would be severely limited in size.
Does this same restriction apply to 4.2?
Any helpful hints or pointers would be appreciated
Please respond directly by mail to
{philabs,ihnp4,cucard,rocky2}!aecom!yechiel
Thanks in advance!
Michael Corndave@uwvax.UUCP (Dave Cohrs) (09/30/84)
> They say its because the UDA-50 uses up too many Address Map Registers > on the Unibus and as a result, the kernel would be severely limited in size. > Does this same restriction apply to 4.2? The big restriction with the UDA for UN*X is that it uses up too much of the bandwidth of the unibus. If you want to get anything done, you'll have to run it on a separate unibus (or things will just be slow). -- (Bug? What bug? That's a feature!) Dave Cohrs ...!{allegra,heurikon,ihnp4,seismo,uwm-evax}!dave dave@wisc-rsch.arpa
charisse@infoswx.UUCP (10/06/84)
We have a VAX 11/750 with an RA81; TU80; RA60 dmf-32 and 2 dz-ll's
all on the same unibus running 4.2BSD. It works just fine.
We have never had a software crash although we do have problems
with tbuf parity errors which are a known problem on the 750. However,
I must add that our load average rarely gets above 2.5 thus we
probably aren't really pushing the system. I would say start out
with one unibus and if that isn't enough add another one, unless
you are considering a massbus drive, but I thought DEC was moving
away from those.
Charisse Castagnoli
{ allegra!convex!infoswx!charisse }