On February 1, Gunther Schadow 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.
This is indeed correct...if you plug an RLV11 into a Q/Q backplane
instead of a Q/CD backplane, for example, you'll let out the magic
smoke.
> 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.
Dunno about the 'QSAs in particular...but in general things should
work, except for cards with 16/18/22 bit address issues.
> Also, why was the need for grant continuity cards an advantage?
It's not an "advantage" per se...just what the bus needs. Several
busses use schemes like this...for example, with some high-speed
peripheral controllers in VME Sun systems, you need to remove the BG3
and IACK jumpers from the other side of the backplane. There are no
grant "cards" but there are indeed grant jumpers.
> The OMNIBUS didn't need it but the UNIBUS (and Q-bus?) do.
Omnibus is a "straight" bus...pin 1 goes to pin 1 on all slots, pin 2
to pin 2, etc...there are no hardware-prioritized "daisy-chain"
signals like those found in some other busses.
> 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
If those slots are all straight Unibus, it likely WON'T work. :)
> 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?
SPC slots..."small peripheral controller" I believe is the correct
expansion of that acronym...you'll want to grab a pdp11 unibus
processor handbook for that info...it's all in there.
> Are there UNIBUS backplanes with more than 9 rows?
None that I've seen. I've seen 4- and 9-slot ones.
-Dave
--
Dave McGuire
St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf
Received on Fri Feb 01 2002 - 16:42:03 GMT