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Punched cards were once common in data processing and the control of automated machines. Punched cards were widely used in the 20th century, where unit record machines, organized into data processing systems, used punched cards for data input, output, and storage. [3] [4] The IBM 12-row/80-column punched card format came to dominate the industry.
A single program deck, with individual subroutines marked. The markings show the effects of editing, as cards are replaced or reordered. Many early programming languages, including FORTRAN, COBOL and the various IBM assembler languages, used only the first 72 columns of a card – a tradition that traces back to the IBM 711 card reader used on the IBM 704/709/7090/7094 series (especially the ...
An IBM 80-column punched card of the type most widely used in the 20th century IBM 1442 card reader/punch for 80 column 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.
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.
These inventions were among the foundations of the data processing industry, and Hollerith's punched cards (later used for computer input/output) continued in use for almost a century. [19] In 1911, four corporations, including Hollerith's firm, were amalgamated to form a fifth company, the Computing-Tabulating-Recording Company (CTR). [20]
A paper tape, constructed from punched cards, in use in a Jacquard loom. The large holes on each edge are sprocket holes, used to pull the paper tape through the loom. Perforated paper tapes were first used by Basile Bouchon in 1725 to control looms. However, the paper tapes were expensive to create, fragile, and difficult to repair.
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."
The punch card project was so extensive and immediate that the War Relocation Authority subcontracted the function to IBM. [1] IBM equipment was used for cryptography by US Army and Navy organisations, Arlington Hall and OP-20-G and similar Allied organisations using Hollerith punched cards (Central Bureau and the Far East Combined Bureau).