PDP-11/35 Details

Published Monday, April 30 2012

Here’s a little more information about the PDP-11/35.

It came to me with the following peripherals:

There are three backplanes (or “System Modules”, as DEC called them) installed. The first is a 9 slot KD11-A, the second is a 4 slot MM11-S, and the third is a 4 slot DD11-A. The MM11-S is interesting in that it suggests that the 11/35 originally came with the MM11 16KW core memory option, though somewhere along the line that was upgraded to MS11 MOS memory.

Here’s the layout:

03M7232 - KD11-A 11/40 Micro Word Module
04M7231 - KD11-A 11/40 Data Paths Module
05M7233 - KD11-A 11/40 IR Decode Module
06M7235 - KD11-A 11/40 Processor Status Module
07M7234 - KD11-A 11/40 Timing Module
09M981 Jumper, M7800 Async Serial
11M7847-BD - MS11-EP 16KW RAM1
12M7847-DJ - MS11-JP 16KW RAM
13M920 Jumper
14DSD 440 Floppy Controller
15ECCO Paper Tape Reader
16G772B, M7800 Async Serial
17M9302 Terminator, G727A
  1. The MS11-JP module is normally an 8KW board, but this one has been field upgraded to 16KW of MOS RAM, minus parity bits on the upper 8KB.