Punched card

Revision as of 14:15, 9 December 2012

Punched cards, or punchcards, were for many years the major method of providing input to computers. Programs in FORTRAN or COBOL or RPG were punched onto decks of cards (one card per program line) on keypunch machines and handed in to be run in batch-processing mode on the computer, which was too massive and expensive to be made available to individuals other than through the mediation of system operators who eventually handed back the output in printed form. Often the function of the programs was to churn through large amounts of data to do number-crunching or other operations on it; this data might also be provided on punchcards (though magnetic tape and paper punched tape were also used). Punchcards could also be found in all sorts of other places, including in the cards you sent back with bill payments (which bore the infamous exhortation, "Do not fold, spindle, or mutilate").

Punchcards actually predated the computer, however, being introduced as a control mechanism for looms (see Jacquard Loom) and later adapted by Hollerith for data-tabulation for the 1890 US Census.

It should be possible to read most standard punch cards with a sheet-fed scanner (simplex is sufficient) and a simple black/white sensing program. No such program is known to exist yet.

• Aperture card
• Hollerith card
• IBM card
  • IBM stub card
• Jacquard Loom
• Korsakov card
• Mark Sense card
• UNIVAC 90-column card
• Votomatic card (used in election ballots)

Resources

• The Douglas W. Jones Punched Card Page