I first worked on CDC CYBER mainframes (64, 170, 730, 7400) and the CYBER 203 and 205 Super Computers (designed by Seymour Cray while he worked for Control Data Corporation) before he started Cray Computing. I wrote Fortran and Assembly language for about 10 years. My division was bought out by Siemens Power System Controls in around 1990. I then transitioned to Oracle, SQL and PL/SQL. The 205 I worked on took up a 60,000 sq ft building. It was a 128 bit vector processing unit.
My undergrad student computing at GA Tech was on a Cyber mainframe. FORTRAN on punch cards for the intro to computing class, later a PASCAL elective on time shared terminals.
Tech had an IBM PC student discount plan when I was a senior (IBM had a huge footprint in Atlanta then), and I bought one. Financed it like a car, which you could have bought a decent used car for what I spent.
So my grad school computing was on an early IBM-PC, used it a lot. I remember using interpreted BASIC to do some hairy numerical method solutions to nasty diff-eqs. The stuff would take hours to converge to a solution, but who cared? I’d get it set up and let it run overnight, have a solution when I woke up. It beat the heck out of having to drive down to the computer center to work on the Cyber, which could do it fast, but not conveniently!