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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.〔Bell, T.F. (1895) '' Jacquard Weaving and Designing'', Longmans, Green And Co.〕 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'',〔(Business automation, Volume 19, Hitchcock Pub. Co., 1972 p.38 )〕〔(Electronic Design, Volume 22, Issues 19-22, Hayden Pub. Co., 1974, pp.79, 195 )〕 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,〔(IBM Archive: Keypunch operators, 1934, Stockholm )〕 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. ==Stamping Jacquard cards, 1801 through 1890== Jacquard cards were said to be ''stamped'' or ''cut'' (not punched). The first Jacquard cards were stamped by hand, sometimes using a guide plate. An improvement was to place the card between two perforated metal plates (hinged together), insert punches according to the desired pattern, then pass the assembly through a press to cut the card. These essentially manual processes were replaced by machines; piano machines (the name taken from the keys), operated by keyboards and comparable in function to unit record keypunches, becoming the most common.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Keypunch」の詳細全文を読む スポンサード リンク
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