[TUHS] Why did PDPs become so popular?

[Ron Natalie]

The PDP-8 and 11 were cheap and this allowed them to be used both in lab situations (I remember working with PDP-8's around 1975 at UofM in non engineering departments like psychological-pharmacology) and at the departmental level, in contrast to the central data centers.    I cut my teeth on the PDP-11/45 (running UNIX) in the Electrical Engineering department.   One of the Biomedical Engineering labs used an LSI-11 running miniunix followed by an 11/23 also running UNIX.   I used PDP-11's in several locations in the Psych department and in the biomedical and opthomological departmetns at the Med School.     All this typically by people they wouldn't let anywhere near the campus computing mainframes.     The CS Department at the UofM taught a OS course (where students wrote one of their own) on a pair of 11's upstairs from the computer center.

Amusingly, on the cloud subject, years later those PDP-11's were getting long in the tooth (and you had to share them single user between a large class).   The computer center downstairs had installed several IBM VM/CMS systems.    We offered to rewrite the course curriculum, very centered on the PDP-11, to allow them to teach it on VM (writing their own hosted OS under VM).   Couldn't convince the faculty.   Made too much sense.