https://en.m.wikipedia.org/wiki/Punched_card https://en.m.wikipedia.org/wiki/Punched_card In a character cell terminal editor we would create data files with o

https://en.m.wikipedia.org/wiki/Punched_card https://en.m.wikipedia.org/wiki/Punched_card In a character cell terminal editor we would create data files with one line per card image. In essence a punch card for fortran as each line. This is not much different than what we do today. Today we create a line for each line of code (or comments). It was just that punch cards required specific columns for code and other controlling characters. With physical cards you would carry boxes of card around. If the cards got dropped you were hosed unless the cards were numbers. We had columns for numbering the cards. But when writing a program from scratch you could not number the cards till the program ran correctly. Much fun! Edit: added details