info-vax@ucbvax.ARPA (11/28/84)
From: Lee Moore <lee@rochester.arpa>
The computing center here has a vax 11/750 that they want to put
a UDA-50, a Deuna and a couple of other perpherials on. As you know,
the UDA-50 and the Deuna are both big pigs on the +5 power supply.
It didn't seem that they could co-exist on the same Unibus.
Looking at the power diagram I see that one power supply feeds the
whole machine (unlike the /780 which has a seperate Unibus power
supply). Now, it seems to me that if they didn't have certain other
hardware options that they could free up some extra amps for the
Unibus. Can one really trade off amps in one part of the machine for
another part of the machine? The manual suggestions it might be possible.
Does anybody have experience in this? I hear that the folks at Stanford
have done this successfully.
thanks,
lee
----
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Physical: 43 01' 40'' N, 77 37' 49'' Winfo-vax@ucbvax.ARPA (11/29/84)
From: sasaki@harvard.ARPA (Marty Sasaki)
The bus is not limited in the amount of power it has, although
the backplane is. You could add another box and some more backplane
space along with more power supply.
I know this doesn't answer your question, but I sort of got tired of
the concept of "not enough power on the Unibus" being bandied about.
Marty Sasaki
Harvard University Science Center
sasaki@harvard.{arpa,uucp}