Before my time, but my understanding is that in ye olden days you'd write out your programs by hand, transcribe it to machine code on punch cards, and then submit the stack of cards for batch processing.
Code was usually written out by hand (and code-reviewed) first before being sent off for compilation. If there was no terminal at home, the first part of that could be done over fax/telephone.
My dad switched into IT in the late 80’s, via community college. So being a community college, they still had a machine that ran on card readers.
As I recall they had a machine that took the “scantron” cards and spit out punched ones.
And I don’t remember if they had it or I just read about it later, but someone did eventually invent a punchcard sorter. You had to number the cards, and then you could stuff a dropped deck into the machine and it would save your bacon.
