DEC M705 vs M7050 in PC05

Noel Chiappa jnc at
Wed Jul 29 15:30:28 CDT 2015

    > From: Johnny Billquist

    > DEC made improved cards in many cases, where they added a 0 at the end
    > of the improved card.

The other thing one will sometimes find (in PDP-11's at least, not sure about
other machines) is that an M7xyz is replaced by the upgraded M8xyz, e.g.
M7265, M7266 (11/34) -> M8265, M8266 (11/34A); M7685 (RM02/3) -> M8685; etc.

Of course, there are plenty that follow no system at all, e.g. M7700 (RK05)
-> M7680.

    > There are also examples where the zero was added, and the new module
    > replace a set of modules that combine to implement a device.

The classic example, to me, being the M780 (KL11) -> M7800 (DL11).


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