At 05:31 PM 2/1/02 -0500, you wrote:
>I read a web article the other day where the guy describes the
>various forms of the Qbus and he also said that you could fry
>certain cards when you stick'em in a wrong version of the Qbus.
>Since I have a uVAX II and a PDP11/03 I would want to know if
>I can mix and much cards with thoese busses or if I would fry
>a K[ZF]QSA board sticking it into the wrong bus.
I don't know that much about Qbus, but I beleive that there are
16bit, 18bit, and 22bit versios of the backplane and perhaps while
some boards may be backwards compatible, it seems unlikely that
the older 16bit boards are forward compatible.
>Also, why was the need for grant continuity cards an advantage?
>The OMNIBUS didn't need it but the UNIBUS (and Q-bus?) do.
>Also, what's the deal about grant continuity cards, they seem to
>just have a few lines shorted. In the UNIBUS box next to my
>VAX 11 it has some intermediary open slots but only one grant
>card plugged in. How could that work? Also, why can you stick
>1x or 2x cards into the different sections, is there a difference
>where you put them? Why is the feed to the UNIBUS only a 2x card
>and where must you plug that? Is it magic? Are there UNIBUS
>backplanes with more than 9 rows?
Again, I know mostly about Unibus, so I am guessing that the OMNIBUS
is not as advanced as the Unibus, which has 4 levels of bus priority,
with devices at the same level responding first if they are closest
to. This is done in a chained fashion, so if a card is not present,
then either a grant card must provide the continuity or wires must be
added to the backplane. Otherwise the signals will not make it past
the open slot.
There are both 4 and 9 slot Unibus backplanes. Also, most processor
backplanes have at least one Unibus slot in them to provide room for
a DL11 console card (or similar). The Unibus comes into the A and B
(top two) connectors of these backplanes and leaves or is terminated
in the last A and B (top two) connectors. Hex cards can be plugged
into the slots which are not on the ends. Quad cards can be plugged
into the end slots. In a 9 slot backplane, only 2 hex cards can be
used. First and last are as viewed from the card side, not the wire
wrap side, with the power wires at the top, and the first on the
right, which is the side that the CPU is placed on.
4321 987654321
+----+ +---------+
|DD11| |processor| A \
| | |backplane| |
|====| |=========| | Unibus
| | | | B | signals
| | | | /
|====| |=========|
| | | | C
| | | |
|====| |=========|
| | | | D
| | | |
|====| |=========|
| | | | E
| | | |
|====| |=========|
| | | | F
| | | |
+----+ +---------+
Viewed from side cards plug into.
--tom
>so many questions :-)
>-Gunther
>
>
>
>--
>Gunther Schadow, M.D., Ph.D. gschadow_at_regenstrief.org
>Medical Information Scientist Regenstrief Institute for Health Care
>Adjunct Assistant Professor Indiana University School of Medicine
>tel:1(317)630-7960 http://aurora.regenstrief.org
>
>
>
>
Received on Fri Feb 01 2002 - 17:00:48 GMT