The personal computer (as a category, not just the IBM PC). I first ran into one in high school, when the computer science lab got five TRS80s. Before that, it was submitting a FORTRAN deck that someone took to an off-site mainframe. Half a week later, you got your results. But with the TRS80, you got them as fast as the program ran.
Now the CS lab did have a Teletype terminal, though I never used it. But the TRS80 had a real interactive display, not just static paper.
I know there were others before the TRS80. It's just the first one I came across.
I am guessing such a long feedback loop required proofreading your code very carefully before submission. Do you still have this skill now when the feedback loop is so much shorter?
I noticed that some very senior programmers check their code for much longer than rookies like me, who just keep banging "Run" until there are no more warnings ;)
Why keep it? If you can find a typo with an hour of inspection, or with a minute of compiling, why do the hour of inspection? Save that for the bugs that will take a day to track down...
Now the CS lab did have a Teletype terminal, though I never used it. But the TRS80 had a real interactive display, not just static paper.
I know there were others before the TRS80. It's just the first one I came across.