Served as both input, output and storage system in the eary days!
Video 1. 1964 IBM 029 Keypunch Card Punching Demonstration by CuriousMarc (2014) Source. Video 2. Using Punch Cards by Bubbles Whiting (2016) Source. Interview at the The Centre for Computing History.Video 3. Once Upon A Punched Card by IBM (1964) Source. Goes on and on a bit too long. But cool still.
Video 1. The 1890 US Census and the history of punchcard computing by Stand-up Maths (2020) Source. It was basically a counting machine! Shows a reconstruction at the Computer History Museum.
Ciro Santilli