2014-04-26 10:52:28 -04:00
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punched card
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2014-04-26 11:54:15 -04:00
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[techspeak] (alt.: punch card ) The signature medium of computing's Stone
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Age , now obsolescent. The punched card actually predated computers
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considerably, originating in 1801 as a control device for mechanical looms.
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The version patented by Hollerith and used with mechanical tabulating
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machines in the 1890 U.S. Census was a piece of cardboard about 90 mm by 215
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mm. There is a widespread myth that it was designed to fit in the currency
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trays used for that era's larger dollar bills, but recent investigations
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have falsified this. IBM (which originated as a tabulating-machine
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manufacturer) married the punched card to computers, encoding binary
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information as patterns of small rectangular holes; one character per
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column, 80 columns per card. Other coding schemes, sizes of card, and hole
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shapes were tried at various times. The 80-column width of most character
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terminals is a legacy of the IBM punched card; so is the size of the
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quick-reference cards distributed with many varieties of computers even
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today. See chad , chad box , eighty-column mind , green card , dusty deck ,
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code grinder.
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