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Punched card. A 12-row/80-column IBM punched card from the mid-twentieth century. A punched card (also punch card[1] or punched-card[2]) is a piece of card stock that stores digital data using punched holes. Punched cards were once common in data processing and the control of automated machines. Punched cards were widely used in the 20th ...
A punched card is a flexible write-once medium that encodes data, most commonly 80 characters. Groups or "decks" of cards form programs and collections of data. The term is often used interchangeably with punch card, the difference being that an unused card is a "punch card," but once information had been encoded by punching holes in the card ...
Three different types of punch cards were used: one for arithmetical operations, one for numerical constants, and one for load and store operations, transferring numbers from the store to the arithmetical unit or back. There were three separate readers for the three types of cards.
A computer punched card reader or just computer card reader is a computer input device used to read computer programs in either source or executable form and data from punched cards. A computer card punch is a computer output device that punches holes in cards. Sometimes computer punch card readers were combined with computer card punches and ...
The heart of the 024 and 026 keypunches was a set of twelve precision punches, one per card row, each with an actuator of relatively high power. Punch cards were stepped across the punch one column at a time, and the appropriate punches were activated to create the holes, resulting in a distinctive "chunk, chunk" sound as columns were punched.
Herman Hollerith (February 29, 1860 – November 17, 1929) was an American statistician, inventor, and businessman who developed an electromechanical tabulating machine for punched cards to assist in summarizing information and, later, in accounting. His invention of the punched card tabulating machine, patented in 1884, marks the beginning of ...
Early machines which were used to tabulate punch cards could only add and subtract. In 1931 IBM introduced an electromechanical multiplying punch, the IBM 601 . After World War II, IBM made a version, the 603 , that used vacuum tubes to perform the calculations. [ 2 ]
Hollerith's method was used for the 1890 census. Clerks used keypunches to punch holes in the cards entering age, state of residence, gender, and other information from the returns. Some 100 million cards were generated and "the cards were only passed through the machines four times during the whole of the operations."