I have two PDP-11/10 units.
The first one has been upgraded to MOS memory before I received it.
The second one still uses core memory.
Both are in working order (or at least they were in working order when I last tested them).
PDP-11/10 with MOS memory
This is a very bare-bones system.
It has 3 backplanes (9-slot, 9-slot and 4-slot). The second backplane holds a hex-height MOS memory board. I was told this machine uses a “Modified UNIBUS backplane”. I am not sure whether this affects all 3 backplanes, or just the second one. Care needs to be taken here.
The backplanes are fitted with the following cards (excluding M920 UNIBUS connectors and grant continuity cards):
- Slot 1: AB = empty. CD = M9970. EF=Empty
- Slot 2: AF = M7260
- Slot 3: AF = M7261
- SLot 4: AB = M930 (terminator?). CF = Empty
- Slot 5-9: Empty
- Slot 4: Plessey P/N 701295-???F (128KW MOS Memory board)
- Slot 6: M7867 (synchronous modem interface)
Unfortunately the suffix on the part number for the Plessey MOS Memory board is unreadable. The board is fitted with 4 rows of 18 x 4116 dynamic RAM chips. I guess this means it has 64KW of parity RAM. That’s a bit surprising, given that the PDP-11/10 only has a 16-bit address space. I need to investigate this further. It has one 10-way dipswitch on the board. Switches 1-7 and 9 are ON. Switches 8 & 10 are OFF.
The DUP11 is a synchronous modem interface. It operates under various protocols (SDLC, ADCCP, DDCMP, etc). The User’s Manual for the DUP11 is available on bitsavers here -> ftp://bitsavers.informatik.uni-stuttgart.de/pdf/dec/unibus/EK-DUP11-OP_DUP11UM_Nov76.pdf
Some grant continuity cards are fitted, but many appear to be missing. There is no terminator at the end of the final (third) backplane.