It'd be annoying if you put one through at the wrong time and had to start again.

How many cards did it take, on average, to enter a program?
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Well, in JCL when you write a line of code, it's called a job card, meaning you had 1 card for 1 line of code (80 characters limit). So imagine a program with 100 lines, you have 100 cards!
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Pure madness, but at the time punch card computers were new they must have seemed amazing.
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What did people do with the data they generated? how did they get the results off and things like that?

Could a punch card based computer do all that much?

I ask becuase I know pretty much sod all about them.
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From what my mum told me about the mainframe she used in the 60's they would select the punch cards needed to retrieve specific records (she worked in the ordering department of a part of Philips) and the computer would then sort the records and print the results onto that whole punched continuous paper. They would then have to go through the printouts to check the records. She didn't actually code and create the punch cards, just use the premade programs to obtain the records needed.
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Read about the IEBPTPCH program so you can get a better notion of what it does, and what "print" means.

IEBPTPCH program
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