Okay, I was introduced to Plato at Mayo HS in Rochester MN, where I was told it was a sort of dial-up to a UM system. No BBS or the like, just a simple programming environment. I wrote codes in a sort of basic-like language with line numbers and stuff, saved them on paper punch tapes. The terminal had cylindrical keys like an old teletype terminal (which it probably was), with only paper print out as the computer-to-human connection. This was the system where I wrote my first modeling program, an empirical solution to the diffraction pattern from a double slit experiment. Full disclosure, they told us a very high price per minute, so when I wrote my first infinite loop I panicked and just unplugged the system to force a reboot.
A very funny episode of Big Bang actually showed how to use a loop counter to break the loop, something I had not yet figured out back in '68, and obviously I was way ahead of the programming support at the high school at the time, so even if I were hiding from the sysadmin, he/she certainly did not live locally. Sigh, time to get out the suspenders and start talking like the Unix guru in Dilbert. I feel old.