Punch card
More info
- Creator
- Herman Hollerith
- Released
- 1890
- Type
- Data medium
- Capacity
- 80 characters per card
The data medium that gave us 80 characters per line — a limit still present in coding standards written by people who never saw a card.
Herman Hollerith designed the card and the machines for the 1890 United States census, cutting processing time from eight years to a couple. The company he founded later became IBM. The card's final form arrived in 1928: 80 columns, one character per column, encoded as holes across twelve rows.
A program was a physical deck, and dropping it meant re-sorting a thousand cards into order — which is why FORTRAN reserved columns 73 to 80 for sequence numbers. The eighty-character limit outlived the medium: it persisted in terminals, then in terminal emulators, and now lives on as a line-length rule in coding standards.