alt Hacker NewsAn old timer once told me about how he would read his printouts, make new punch cards, send them over to the main office, someone would put the new cards into the system the next morning, and then read the printouts on the day after that to see if his code worked or not.
This. Except worse, during busy days you had to stand on line for an hour or more for a turn on the machines. I believe the skill of debugging by mentally stepping through a program's execution came from such long run times, a useful skill many younger programmers lack.