7 Mar
2016
7 Mar
'16
10:25 a.m.
I see on the usual site, an 11/23 box with a couple of random boards,
one of which is an M7608 board. This is a Microvax memory board.
I wonder if one can build up a Microvax in that backplane, or if that is
not recommended. It would obviously be an 18 bit backplane. The
backplane is H9276A.
The auction also has a M9047 Bus grant card in it, so is essentially
just the box. But I'd never seen Microvax parts plugged into those
backplanes, and it made me think.
thanks
Jim
7 Mar
7 Mar
11:10 a.m.
On Mon, Mar 7, 2016 at 10:25 AM, jwsmobile <jws at jwsss.com> wrote:
I see on the usual site, an 11/23 box with a couple of
random boards, one of
which is an M7608 board. This is a Microvax memory board.
I wonder if one can build up a Microvax in that backplane, or if that is not
recommended. It would obviously be an 18 bit backplane. The backplane is
H9276A.
The auction also has a M9047 Bus grant card in it, so is essentially just
the box. But I'd never seen Microvax parts plugged into those backplanes,
and it made me think.
The H9273 is a 9 row Q18/CD backplane and the H9276 is a 9 row Q22/CD
backplane. I don't see why you couldn't build up a QBus MicroVAX in an
H9276 backplane. You'd have to hack up something to mount the console
bulkhead panel in a BA11 box instead of the standard BA23 box.
11:54 a.m.
On 07/03/2016 18:25, jwsmobile wrote:
I see on the usual site, an 11/23 box with a couple of
random boards,
one of which is an M7608 board. This is a Microvax memory board.
I wonder if one can build up a Microvax in that backplane, or if that is
not recommended. It would obviously be an 18 bit backplane. The
backplane is H9276A.
That's a 22-bit backplane so I don't see why you couldn't build a
microVAX in it. Bear in mind it's all straight QQ-CD, unlike BA23 and
BA123 backplanes normally used for microVAXen, which have serpentine
sections and can hold more cards.
--
Pete
8 Mar
8 Mar
4:41 a.m.
New subject: BA23 Box with RLV11 (Was: 11/23+ box with Microvax Memory)
jwsmobile wrote:
I see on the usual site, an 11/23 box with a couple of
random boards,
one of which is an M7608 board. This is a Microvax memory board.
I wonder if one can build up a Microvax in that backplane, or if that
is not recommended. It would obviously be an 18 bit backplane. The
backplane is H9276A.
The auction also has a M9047 Bus grant card in it, so is essentially
just the box. But I'd never seen Microvax parts plugged into those
backplanes, and it made me think.
thanks
Jim
Probably not as unexpected, but just as unusual in my mind:
I once saw a BA23 box with an M8190-AB (PDP-11/73) CPU
in slot 1 followed by an RLV11 (M8013 / M8014) in slots 2 / 3
connected to an RL02 drive. Usually, by the time a system
had a PDP-11/73 board, a couple of MB of memory and an
RL02 drive, the RL02 controller was upgraded to an RLV12
(M8061) board. NOTE that slots 2 / 3 had to be used for
the RLV11 since they were the only 2 slots left with ABCD.
Placing the RLV11 in any other position in a BA23 box lets
out the magic smoke.
As a bit of additional information, the other 5 slots were used
to hold the memory and other modules that were required. There
did not seem to be any problem with the memory being placed
in slot 4.
Jerome Fine
3211
days inactive
3212
days old
3 comments
4 participants
participants (4)
-
glen.slick＠gmail.com -
jhfinedp3k＠compsys.to -
jws＠jwsss.com -
pete＠dunnington.plus.com