The Apollos had their own Display Manager. (At least, by the time I saw them, as they were almost being discontinued, when they ran Domain/OS SR10.) It had a

The Apollos had their own Display Manager. (At least, by the time I saw them, as they were almost being discontinued, when they ran Domain/OS SR10.) It had a lot of neat things about it, including being ahead of its time and thinking behind Unix. But often people just used it to run a single program, and spend much time in the rest of the system.