UNIBUS RAM with Parity vs. None

Eric Smith spacewar at gmail.com
Fri Oct 9 17:53:36 CDT 2015

> Anyone disagree, and if so why did DEC want their 11/05 S to use "D" model
> core (D=parity) and not C (C=no parity)?  The PDP 11/40 I have uses C.

The H217D is the no-parity plane, and the H217C has parity.

For the parity to do anything useful, you have to also have an M7259
module, and IIRC the 11/05 backplane is not wired for it.

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