PDP-11
UNH had a few PDP-11s, but I did exceedingly little programming on them. I preferred writing Fortran and Assembly on the DEC-10 they had and mostly used the PDP-11s to get killed, repeatedly, in Zork.
Once I got kicked out of left UNH (of my own free will and an
agreement with the judge to never set foot on campus again), and
settled in at UNM, that changed. UNM's IT Support (then called CERT,
I believe), had a PDP-11/70 that ran UNIX. In fact, it ran the
Berkeley Software Distribution of UNIX (2.x BSD). I programmed in C
on that machine and even made a tiny contribution
or two.