Punch card

The punch card (or "Hollerith" card) is a recording medium for holding information for use by automated data processing machines. Made of stiff cardboard, the punch card represents information by the presence or absence of holes in predefined positions on the card. In the first generation of computing, from the 1920s into the 1950s, punch cards were the primary medium for data storage and processing. Eventually the punch card would be phased out and replaced with huge floppys for media storage, for loading data, in the late 1970's, early 1980's.

Origins

The punched card predates computers considerably. As early as 1725 Basile Bouchon used perforated paper loop in a loom to establish the pattern to be reproduced on cloth, and in 1726 his co-worker Jean-Baptiste Falcon improved on his design by using perforated paper cards attached to one another, which made it easier to quickly change the program. The Bouchon-Falcon loom was semi-automatic and required manual feed of the program. Joseph Jacquard used punched cards in 1801 as a control device for the more automatic Jacquard looms, which met with great success.

Related Topics:
Computers - 1725 - Basile Bouchon - 1726 - Jean-Baptiste Falcon - Joseph Jacquard - 1801 - Jacquard looms

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Charles Babbage, who originated the idea of a programmable computer, adopted Jacquard's system of punched cards to control the sequence of computations in the design for his analytical engine in 1837 http://www.cs.uiowa.edu/~jones/cards/history.html. Such cards were used as an input method for the primitive calculating machines of the late 19th century. The version by Herman Hollerith, patented on June 8, 1887 and used with mechanical tabulating machines in the 1890 U.S. Census, was a piece of cardboard about 90 mm by 215 mm, with round holes. This was the same size as the dollar bill of the time, so that storage cabinets designed for money could be used for his cards. The early applications of punched cards all used specifically-designed card layouts. It wasn't until around 1928 that punched cards and machines were made "general purpose". In that year, punched cards were made a standard size, exactly 7-3/8 inch by 3-1/4 inch (187.325 by 82.55 mm), reportedly corresponding to the US currency of the day, though some sources characterise this assertion as urban legend.

Related Topics:
Charles Babbage - Analytical engine - 1837 - 19th century - Herman Hollerith - June 8 - 1887 - 1890 - U.S. Census - 90 - Mm - Dollar bill - Inch - US currency of the day - Urban legend

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To compensate for the cyclical nature of the Census Bureau's demand for his machines, Hollerith founded the Tabulating Machine Company (1896) which was one of three companies that merged to form IBM in 1911.

Related Topics:
1896 - IBM - 1911

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The IBM 80-column punching format, with rectangular holes, eventually won out over the UNIVAC 90-character format, which used 45 columns (2 characters in each) of 12 round holes. IBM (Hollerith) punched cards are made of smooth stock, .007 of an inch thick. There are about 143 cards to the inch thickness; a group of such cards is called a deck. Punch cards were widely known as just IBM cards.

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