> 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.