6 Jan
2011
6 Jan
'11
2:03 a.m.
Thank you Ethan for a comprehensive answer.
Checking
http://world.std.com/~mbg/pdp11-field-guide.txt, your memory
pile looks like:
A great document! I wouldn't know what to do without it.
M8043: DLV11 - a quad serial card (those four 40-pin
DIPs are UARTs, not SRAM)
M8044: MSV11-D - if full (most are), it's an MSV11-DD, a 32Kword RAM
card - small for a large system
M8047: MXV11 - probably a 16Kword card w/SLUs - also small for a large system
M8059: MSV11-L - either -LF (64Kword) or -LK (128Kword) - medium-sized
M8067: MSV11-P - either -PF (128Kword) or -PK (256Kword) or -PL
(512Kword) - large for DEC
M7506: MSV11-M - either -MA (256Kword) or -MB (512Kword)
Your limits are 2Mword (4Mbytes) of total Qbus memory on a 22-bit
system. In my experience, few Qbus machines had more than 4 memory
boards of any size, most had 1-2 (if you needed to add more memory, it
was "more economical" to remove the older, smaller stuff and use the
same number of slots with larger capacity cards.
It seems that I'm lucky my M7506 is -BF which is 512KW (any idea why the
field guide above lists it as 1MB?) and that my M8067 is -PL also 512KW.
So in total I think I will have 2MW :) if everything is functional that
is. So I will hang on to those, I'll also keep a M8059 or two if the
bigger boards are broken.
Not quite.
There is a variant (Rev A) of the KDF-11 (11/23) CPU card that can't
go above 18 bits, but I've never seen one in the field. Every one
I've seen can work in an 18-bit or 22-bit chassis. That's the
limiting factor - what's your backplane? A post-rev-A KDF-11 in a
BA23 has no problems with being configured as a 22-bit system. It's
also possible to run wires to upgrade an 18-bit backplane to 22-bits -
many of us on the list have done that.
I have a H9273, a 4x9 18bit CD backplane. No upgrade done.
The RLV12 is a keeper - it works in 18 or 22-bit
machines and it
doesn't have the limitation of needing to be stuffed into a
CD-interconnect slot (unlike the two-board RLV11). The RQDXE is handy
if you want to use an RQDX3 in a system other than a single-BA-23
cabinet. If I were keeping memory, I'd keep the larger of your cards
(MSV11-L, -P, -M) and populate the departing 11/23 with the MSV11-D
(as long as you have a serial card for its console, like the DLV11-J,
otherwise, you can configure a small system with the MXV11).
It will be a complete system with KDF11, DLV11, MSV11, RLV11 and BDV11
plus a bunch of spares, a fairly nice 11/23 setup as 11/23s goes.
I hope all this information helps rather than obscures
your task.
I has indeed helped! Thank you.
- Pontus