29 Jul
2015
29 Jul
'15
1:30 p.m.
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).
Noel