Difference between revisions of "MM11-Y core memory"
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* [https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/05%20Unibus%20Options/MM11-YP%20G657%20M7850%2032K%20x%2018%20Core%20Memory/ MM11-YP Memory Module Field Maintenance Print Set] (MP-00317) | * [https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/05%20Unibus%20Options/MM11-YP%20G657%20M7850%2032K%20x%2018%20Core%20Memory/ MM11-YP Memory Module Field Maintenance Print Set] (MP-00317) | ||
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[[Category: UNIBUS Memories]] | [[Category: UNIBUS Memories]] | ||
Revision as of 22:52, 3 June 2022
The MM11-Y was a 64 Kbyte core main memory for PDP-11 UNIBUS machines. It provided parity, so its formal name was MM11-YP.
An MM11-Y was composed of two hex boards, one piggy-backed on the other, and the pair taking only a single backplane slot (electrically):
- An H228-B daughter-board containing the cores
- A G657 mother-board containing most of the electronics, and the contact fingers for plugging into a backplane
The MM11-Y did not use a custom backplane; it plugged into a standard MUD slot. The pair was 'thick' enough that a normal board cannot be plugged into the next slot; instead, a G727 grant continuity card must be used there (since it has no components on it, it just clears the H228-B card).
The core array provided two more bits per word, to support byte parity; parity operation used an M7850 parity controller plugged into the same backplane as the MM11-D.
It is possible to interleave a pair of MM11-Y's to provide reduced effective average access times.
Further reading
- MM11-YP User's Manual (EK-MM1YP-UG) - not available online
- MM11-YP Technical Manual (EK-MM1YP-TM-001) - not available online, exists in fiche
