Sixth Edition is from 1975. Let's consider its contemporary large-scale multiuser OS environments: * PLATO at UIUC. Much more sophisticated graphics and extensive support for multiuser gaming, but requires custom (and expensive) terminals. Homegrown mainframe, then CDC hardware. * Michigan Terminal System at University of Michigan and elsewhere. Runs on IBM mainframes. * Multics, ITS, TOPS-10, and who knows what else…
This omits a bunch of others -- WYLBUR supported interactive program development on IBM mainframes at several universities, for example. (The "large scale" qualifier here is also a little bit dubious -- it seems to be a way of saying that anything running on a machine as small as a PDP-11 doesn't count. But there were timesharing systems on even smaller machines, such as PDP-8s.)
Re: Research Unix Sixth Edition (WASM)
#31By "large scale" I meant something used by, well, a lot of people. More than a university's CS department (or the math or EE department; whichever side had the proto-CS faculty in 1975). Like, V6 was being used across Bell Labs, but I wouldn't call that a large-scale deployment compared to MTS, let alone DTSS. When V6 was ported to IBM mainframes by Eric Schmidt and others, that didn't result in Unix being made available to any Princeton student who wanted an account. Nor did the Interdata port result in a campuswide Unix system for all Wollongong students. In both cases, had a random student wanted a computer account and was eligible for one, he would have received something on a batch system.