22 Jun
2016
22 Jun
'16
5:28 p.m.
On Tue, Jun 21, 2016 at 9:05 PM, Michael Thompson <
michael.99.thompson at gmail.com> wrote:
The RICM just picked up a PDP-11/40 chassis that was
modified to accept a
PDP-11/23 board set. It also contains a custom board to interface the
PDP-11/23 to the original PDP-11/40 front panel. It is quite an
accomplishment to get the Q-Bus board set working in the Unibus chassis.
I looked at the backplane pictures that I took after the rescue. I assumed
that the hex-wide 8-slot backplane in the front of the card cage was the
original 11/40 processor backplane. On the back it says "LSI 11 BACKPLANE",
so the operation is not so mysterious. I had never seen a hex-wide Q-bus
backplane before this.
There are some pictures of the system and the Q-Bus to 11/40 front panel
interface here: http://www.ricomputermuseum.org/Home/equipment/dec-pdp-1140
--
Michael Thompson
22 Jun
22 Jun
5:35 p.m.
On Wed, Jun 22, 2016 at 8:28 PM, Michael Thompson
<michael.99.thompson at gmail.com> wrote:
I looked at the backplane pictures that I took after
the rescue. I assumed
that the hex-wide 8-slot backplane in the front of the card cage was the
original 11/40 processor backplane. On the back it says "LSI 11 BACKPLANE",
so the operation is not so mysterious. I had never seen a hex-wide Q-bus
backplane before this.
I have one... it came to me in an 11/34 with a lone IVB11 mounted in
it (Qbus IEEE-488) from a Physics Lab, and might have been marked on
the paper label DDV11CK. It was all DEC, no Abel Qniverter, but I
can't recall what DEC module was on the Unibus to drive the Qbus (the
Qbus input paddle card was one of the ordinary ones used in a BA11N or
similar).
I never got the history, but presumably, some time in the late 1970s,
Ohio State ordered a PDP-11/34 with IEEE-488 and for whatever reason
(no IB11 available? IB11 EOLed?), it came with an IBV11 and a bus
converter. I'd like to dig that one out someday and try a Qbus SCSI
card on a Unibus machine. It'll probably work if I can get a
bootstrap on the box.
There are some pictures of the system and the Q-Bus to
11/40 front panel
interface here: http://www.ricomputermuseum.org/Home/equipment/dec-pdp-1140
Neat!
I've dug into the 11/70 front panel schematics, so I'm pretty sure
it's "easy" to get the Qbus to drive the LEDs, at least the address
and data LEDs, but I'm wondering about the switches and how many of
them work.
-ethan
5:50 p.m.
On Wed, Jun 22, 2016 at 5:28 PM, Michael Thompson
<michael.99.thompson at gmail.com> wrote:
I looked at the backplane pictures that I took after the rescue. I assumed
that the hex-wide 8-slot backplane in the front of the card cage was the
original 11/40 processor backplane. On the back it says "LSI 11 BACKPLANE",
so the operation is not so mysterious. I had never seen a hex-wide Q-bus
backplane before this.
There are some pictures of the system and the Q-Bus to 11/40 front panel
interface here: http://www.ricomputermuseum.org/Home/equipment/dec-pdp-1140
Maybe a DDV11-B? See pages 205-210 of the PDP-11 Microcomputer
Interfaces Handbook 1983-84:
http://www.bitsavers.org/pdf/dec/qbus/EB-23144-18_QbusIntrfs_1983.pdf
The screws on the connector blocks in groups of 1 on the first and
last rows and 3 in the center rows looks similar to those shown in
Figure 2 DDV11-B Module Installation and Slot Assignments on page 207.
3104
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ethan.dicks＠gmail.com -
glen.slick＠gmail.com -
michael.99.thompson＠gmail.com