What is "keypunch"

1933, from keyboard (which operated it) + punch (v.), which is what it did to the cards inserted in it to record date.\n

n. 1 (context computing English) A device, in which one or a combination of keys are pressed to punch holes in punched cards or paper tape that correspond to a particular character 2 (context computing English) an electric machine with a keyboard that has the same function vb. To use such a device or machine

A keypunch is a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator.

For Jacquard looms, the resulting punched cards were joined together to form a paper tape containing a program that, when read by a loom, directed its operation.

For Hollerith machines and other unit record machines the resulting punched cards contained data to be processed by those machines. For computers equipped with a punched card input/output device the resulting punched cards were either data or programs directing the computer's operation.

Early Hollerith keypunches were manual devices. Later keypunches were electromechanical devices which combined several functions in one unit. These often resembled small desks with keyboards similar to those on typewriters and were equipped with hoppers for blank cards and stackers for punched cards. Some keypunch models could print, at the top of a column, the character represented by the hole(s) punched in that column. The small pieces punched out by a keypunch fell into a chad box, or (at IBM) chip box, or bit bucket.

In many data processing applications, the punched cards were verified by keying exactly the same data a second time, checking to see if the second keying and the punched data were the same (known as two pass verification). There was a great demand for keypunch operators, usually women, who worked full-time on keypunch and verifier machines, often in large keypunch departments with dozens or hundreds of other operators, all performing data input.

Keypunches were popular through the 1970s but were rapidly made obsolete by changes in the data input paradigm and by the availability of inexpensive CRT computer terminals.