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From: KVC@ENGVAX.UUCP (Kevin Carosso)
Newsgroups: mod.computers.vax
Subject: Unibusses (unibi?) on an 8600...
Message-ID: <8603120921.AA08274@csvax.caltech.edu>
Date: Wed, 12-Mar-86 04:22:32 EST
Article-I.D.: csvax.8603120921.AA08274
Posted: Wed Mar 12 04:22:32 1986
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I asked info-vax several days ago about adding an extra UNIBUS to an IDTC
equipped 8600...  We did this successfully, and since I only got one response
from the net, I figure no one else knows the answer, so I thought I'd let
you all know what happened.

It turns out that there is actually room for 3 UNIBUSes in an 8600 CPU cabinet.
There's the UBA that goes to the drawer in the frontend cabinet, the IDTC
which is a UBA and UDA-50 and TU-81 controller slipped into a special set
of slots at the far right, and a regular four board options slot between
the two where the UBA boards from my 785 slid right in!  (the slots are
labelled with the module numbers for a DW780, so you can't miss 'em).

So, we've got a total of 3 UNIBUSes (at TR 3, 4, and 5) without going into
the expansion cabinet.  There's still room for another SBI interface and a
CI interface in the cabinet.

I don't know why the VAX System Options and Summary calls one UBA a DW780-MA
and the other a DW780-MB, nor why it isn't clear about the fact that an
IDTC does NOT use up your second UNIBUS slot, but that's about par for the
course for the VSOS.

	/Kevin Carosso              engvax!kvc @ csvax.caltech.edu
	 Hughes Aicraft Co.