Those old enough to have encountered punch cards in their lifetime are probably ... onto which small black pieces are placed. A white background stud encodes a logic “zero”, while a black ...

(1) See loyalty punch card. (2) An early storage medium made of thin cardboard stock that held data as patterns of punched holes. Also called "punched" cards, each of the 80 or 96 columns held one ...

About thirty years ago [H. P. Friedrichs] pulled off a hack that greatly improved the process of programming with punch cards. At the time, his school had just two IBM 029 keypunch machines.