Probably my favorite example of this is this guy's demonstration of an Altair 8800, one of the earliest PCs, back when they had physical switches on the front p

Probably my favorite example of this is this guy's demonstration of an Altair 8800, one of the earliest PCs, back when they had physical switches on the front panel which you would use to manually enter machine code for the computer to run. Scroll down to the bottom for the earliest videos to see the introductory demonstrations. He builds on that to show how data was loaded from paper punch tape, then later audio cassettes and external disk storage: https://www.youtube.com/user/deramp5113/videos https://www.youtube.com/user/deramp5113/videos