PDP-11/93 and PMI Memory

Jerry Weiss jsw at ieee.org
Thu Apr 18 23:44:30 CDT 2019

The second memory boards CSR should be viable in ODT.

The toggle switch internal contacts may be tarnished with age. Cycle 
each switch, that is used in the on position, multiple times and see if 
the CSR appears.
Try another CSR if necessary to confirm the memory board is responsive 
to Q-bus requests.

Which memory board and rev? MSV11-JE (M8637-E)?


On 4/18/19 8:20 PM, Bill Gunshannon via cctalk wrote:
> Well, I was finally able to get a PMI memory board to expand my
> 11/93 to the full 4 Meg.  (Thanks Paul!)
> I thought it would be as simple as configuring what bank I wanted
> it to fill and inserting it (in front of the CPU).  Sadly, that
> didn't work.  First problem is the only document i could find is
> not for the actual version of the board I  have.  It has the same
> switch sets so I tried it anyway.  Set it to be in the upper 2Meg
> and gave it the next CSR after the on board memory.  No luck.
> 11/93 still reports 1024KWords and the Map command shows neither
> the additional memory or the second memory CSR.
> Anybody have any experience with this? Is there a switch I have to
> change on the CPU module to make it recognize the additional external
> memory?  IS there something about PMI that I am missing?
> Any advice gratefully appreciated.
> bill

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