[kjs3]

That's kinda funny...we musta lived in parallel worlds.

The 3B20 might have been slow, but it had a solid I/O subsystem so you could load it up with users, and was generally reliable (it was originally built as a telco switch control processor looking for 5-nines uptime). But by the later 80s the industry had moved on, and we were in the process of migrating those CS classes from the 3B20 to either a Sequent Symmetry (follow-on to the Balance with something like 16x i386) or a Pyramid 90x, depending on the class. The Symmetry was...not reliable. The 90x was worse. The wails of a lab full of undergrads realizing the shared machine had just taken a dirt-nap and all their work with it was a far too common sound. Good times.

We also had a bunch of 3b2s, most with an AT&T 5620 'windowing terminal' attached, which is a really fascinating 'what might have been' if bitmapped workstations and X11 hadn't taken over that niche. I ended up with a Sun 3/160 for most of that time, and the rest is history.

[flyinghamster]

Strange that the Balance was largely reliable. I recall one or two hiccups, but nothing that caused me lost work. There were other machines floating around, but they were pretty much reserved for faculty/staff/grad students, and undergrad plebes weren't welcome to use what passed for the internet at the time (but Usenet was was available, albeit via Ray Essick's "notes" software). Also, any student could get an account on the CDC Cyber 170, but few courses used it for actual coursework by the time I was there. Then there was PLATO, a world unto itself... it also ran on CDC hardware, with bespoke way-ahead-of-its-time touchscreen plasma display terminals, online forums, instant messaging, and multi-player online games.

We only had a few of the 5620s in the 3B2 lab, and I remember a wacky mechanical mouse with a metal ball that I can't imagine would have held up in the long run. The PLATO touchscreens were optical, with a grid of infrared beams to pick up touches.

[kjs3]

Ha! We (gatech) were a CDC shop as well, with PLATO. We'd moved up to the Cyber 180s (I think we had a 810, 2 x 855 and a 990 vector machine). FORTRAN on the 990 was pretty fun, and I might be the last person to ever run the ALGOL-60 compiler.