MS11-K MOS memory

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The MS11-K MOS memory modules were the first generation of memory array modules used in the MK11 memory system for the PDP-11/70.

MS11-KE 64KB module

Each MS11-K module was a hex board, the M7984. Fully populated, the board holds a total of 156 DRAM chips, including 28 to hold the ECC. According to the prints, it could be used with 4Kx1 chips, giving 64KB total storage; or 16Kx1.

Per the prints, these are the configurations and board types:

Board Model Size Configuration
M7984-Ax MS11-KA 64KB 156 x 4K chips
M7984-Bx MS11-KB 32KB 78 x 4K chips
M7984-Cx MS11-KC 256KB 156 x 16K chips
M7984-Dx MS11-KD 64KB 39 x 16K chips
M7984-Ex MS11-KE 64KB 156 x 4K chips
M7984-Fx MS11-KF 128KB 78 x 16K chips

(The 'x' in the board number is one of a number of letters, starting with 'A', which indicates the manufacturer of the DRAM chips used.)

It is not clear what the difference is between the -KA and the-KE.