What Does Keypunch Mean?

A keypunch or key punch is a device used for precisely punching holes in specific locations on a stiff card. It was used in conjunction with early punched card computers. The punched card served as the program instruction for the computer. The locations of the punches were determined by the keys being struck by a human operator, much like typing on a keyboard. An example of a device that made use of punched cards created by a keypunch device is the Jacquard loom, named after its inventor Joseph Marie Jacquard; the punched cards directed the loom’s operation.


Techopedia Explains Keypunch

Keypunch is a punching device for punched cards used in early computers and was about the only way to feed information to a computer. Early devices such as the Hollerith keyboard punch or pantograph were manual devices that required an operator to punch in the data on a keyboard, which, in turn, activated the appropriate punchers to make holes on the card. In order to verify that the data the operator keyed in were correct, the operator had to do a second keying to the card and determine whether the holes were punched in the same place; if even one hole was out of place, the punched card had to be discarded and the process had to be redone. This manual mechanical punching process started with the Jacquard loom in 1801. Herman Hollerith’s card punchers appeared in 1890 and were used until the introduction of electromechanical punchers in 1923 by the Computing Tabulating Recording Company (CTR), which later became IBM in 1924.

The first electromechanical keypunch was the Type 011 Electric Keypunch, which used electricity-activated solenoids to punch the holes. In 1928, IBM introduced the 80-column punched card format, which was quickly adopted by current models of keypunchers.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…