My classiccmp non-retirement :-)

[Al Kossow]

This raises an interesting question: if you replaced a real PDP-11 that
people connected to online with an emulated one, would they be able to
know the difference?

--

If you were using SIMH you would, since it doesn't perform cycle
accurate simulation. Unless you ran it on fairly slow modern hardware
it would be faster than the original.

This wouldn't be the case for MESS, though, since it is based on
the cycle-accurate MAME processor cores.