I started working with them in the mid 1970s. They were about the size of a modern day dishwasher. Had platters - like vinyl records stacked about 5 high. I think they stored 400 MB. They were so big and expensive that peripherals were shared amongst several computers and I worked on a peripheral switch - how to switch hard drives, tape drives, paper tape, etc between computers. I remember getting an IBM PC with a hard drive for the first time. Probably mid 1980s. 10 MB instead of floppy disks. We thought we had it made.

Do you mean wrote the program down on paper and then created the punch cards? I was about 13 and it was about 1973. It was a Monroe Calculator that was programmable like computers. They had special worksheets that you wrote your program down on. And then hand punched cards to match the worksheet.