MSV11-L MOS Random-Access Memory

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MSV11-L card

The MSV11-L (M8059) is a dual-height QBUS DRAM main memory card. The MSV11-LK (M8059-Kx) holds 256 KBytes when fully populated with 64K DRAMs chips, the MSV11-LF (M8059-Fx) is half-populated (the only partially-filled configuration allowed) and holds 128 Kbytes. (The 'x' in the board identifier is a capital letter which identifies the manufacturer of the DRAM chips.)

The memory is arranged as 2 banks, each 16 data bits (1 PDP-11 word) wide, with 2 additional bits for parity (1 per byte). It can be configured as either a Q18 card, or a Q22 card.


The card is configured by jumpers on wire-wrap posts; it is possible to set:

  • the starting address;
  • the size (256KB or 128KB);
  • the CSR address;
  • parity enable;
  • parity error action;
  • enable wrong parity;
  • bank disable.

Further reading

  • MSV11-L User Guide, EK-MSV0L-UG
  • MSV11-L Field Maintenance Printset (MP-01238 (M)