> you would have to do a lot of work to sort them again in the correct order of the program Actually, there were machines called card sorters that could sort c

> you would have to do a lot of work to sort them again in the correct order of the program Actually, there were machines called card sorters that could sort cards back into the right order.[1] In the card images shown on this page, you can see that there are sequential serial numbers in columns 73 - 80, which could be used to sort these cards. Many programming languages, such as Fortran, would ignore anything punched after column 72, allowing columns 73 - 80 to be used for this purpose. [1] https://en.wikipedia.org/wiki/IBM_card_sorter https://en.wikipedia.org/wiki/IBM_card_sorter