Punched card

Used Punchcard (5151286161)

Jacquard.loom.cards

DMM 29263ab Jacquardwebstuhl

This is a card puncher, an integral part of the tabulation system used by the United States Census Bureau to compile... - NARA - 513295

Keypunch operator 1950 census IBM 016

Punched card program deck.agr

Punched card or punch card is a piece of stiff paper that can hold digital data represented by the presence or absence of holes in predefined positions. Punched cards were used primarily during the 19th and early-to-mid 20th centuries for controlling textile looms, for data storage, and for programming early computers. They are now largely obsolete, replaced by more compact and versatile forms of data storage and transmission.

History

The concept of punched cards was first used in the weaving industry by Joseph Marie Jacquard, with the invention of the Jacquard loom in 1804. This loom used punched cards to control the weaving of complex patterns, significantly reducing the amount of manual labor required. The idea was later adapted for use in data processing and early computing devices.

In the late 19th and early 20th centuries, punched cards were used in the tabulation of census data. Herman Hollerith, an American inventor, developed a punched card system to process the 1890 U.S. Census data, founding the Tabulating Machine Company, which eventually became part of IBM.

Design and Operation

A standard punched card, often referred to as an IBM card, is a piece of cardstock that contains 80 columns and 12 rows. Each column represents a character of data, and the combination of holes in different positions represents different characters. The cards are fed into a card reader, which detects the holes by mechanical or optical means and converts the patterns into digital data.

Applications

Punched cards were used in a variety of applications, including:

• Data storage: Before the advent of magnetic storage, punched cards were a primary medium for storing data.
• Computer programming: Early computers, such as the IBM 704 and UNIVAC I, were programmed using punched cards.
• Voting systems: Some voting systems used punched cards to record votes, though these systems have largely been phased out due to issues with reliability and accuracy.

Decline

The use of punched cards began to decline in the 1970s with the advent of more compact and efficient forms of data storage, such as magnetic tape and disk drives. The development of personal computers and the increasing use of digital storage formats further accelerated the decline of punched cards.

Legacy

Despite their obsolescence, punched cards hold an important place in the history of computing and data processing. They represent one of the first methods of data input and storage that could be processed automatically, paving the way for the development of modern computing technology.