punched card

The punched card is a cardboard with some determinations to be punched, which supposes a binary code . These were the first means used to input information and instructions to a computer in the 1960s and 1970s . Punch cards were not only used in computing, but also by Joseph Marie Jacquard on the looms , from where they really arose.

Currently punched cards have fallen into replacement by magnetic and optical means of information entry. However, many of today’s storage devices, such as CD-ROM, are also based on a method similar to that used by punch cards, although of course the sizes, access speeds and capacities of current media do not support comparison. with the old cards.


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  • 1 History
  • 2 Card formats
    • 1 Hollerith punch card formats
    • 2 UNIVAC 90-character punch card
    • 3 IBM 80-column format punch card
    • 4 Mark sense cards
    • 5 Opening cards
    • 6 IBM 51-column punch card
  • 3 IBM Portable Drill
  • 4 See also
  • 5 Source


Punched cards were first used around 1725 by Basile Bouchon and Jean-Baptiste Falcon as a more robust form of the punched paper rolls used at the time to control textile looms in France . Charles Babbage launched the idea of ​​using punch cards as a way to control a mechanical calculator that he himself designed. Herman Hollerith developed the processing technology of data punch cards for the census of the United States in 1890 and founded the company Tabulating Machine Company ( 1896) which was one of three companies that joined together to form the Computing Tabulating Recording Corporation (CTR) , later renamed IBM .

IBM manufactured and marketed a variety of recording machine units for creating, sorting, and tabulating punch cards, even after expanding into computers in the late 1950s. IBM developed punch card technology as a powerful tool for business data processing and produced an extensive line of general-purpose recording machine units. By 1950, IBM cards and IBM registration machine units had become indispensable in industry and government.

From 1900 to 1950 , punch cards were the first medium for data entry and storage, and processing in institutional computing and according to IBM archives: “By 1937 […] IBM had 32 presses working in Endicott, NY , printing, cutting and stacking 5 to 10 million punch cards every day. ” The punched cards were even used as legal banknotes, as well as checks and savings bonds from the government of the United States of America . During the 1960s, punch cards were gradually replaced as a first measure by data storage on magnetic tapes., as better and more capable computers became available.

Punch cards were still commonly used for data entry and programming until the mid-1970s, when the combination of lower-cost magnetic disk storage and affordable interactive terminals on cheaper minicomputers made punch cards obsolete for this as well. role. However, its influence lives through many standard conventions and file formats. Today, punch cards are largely obsolete and replaced by other storage methods, except for specialized applications.

Card formats

In the early applications of punch cards all used specifically designed card layouts and their usefulness was not known at first for what it was. It wasn’t until around 1928 that punch cards and machines were made “general purpose”. The rectangular, circular or oval bits of paper are called chad (recently, chads) or chips (in IBM slang). Multi-character data, such as words or large numbers, were stored in adjacent columns on the card, known as fields. A group of cards is called a deck.

An upper corner of the card was normally cut off, so that cards that were not oriented correctly, or cards that had different corner cuts, could be easily identified. The cards were commonly printed, so that the position of the row and column of a perforation could be identified. For some applications, the print might have fields included, named and marked by vertical lines, logos, and more. One of the most commonly printed punch cards was the IBM 5081. What’s more, it was so common that other card vendors used the same number (see image to the right) and even users knew that number.

Hollerith punch card formats

Patented perforated card Hollerith the 8 of June of 1887 and used in the machines tabulating mechanical in the census 1890 of United States of America, it was a piece of cardboard of about 90mm by 215mm, with round holes and 24 columns. This card was the same size as a US dollar at the time.

UNIVAC 90-character punch card

The Remington-Rand UNIVAC punch card format had round holes. There were 45 columns with 12 places to punch each, and two characters for each column.

IBM 80-column format punch card

This IBM card format, designed in 1928 , had rectangular holes, 80 columns with 12 punch locations each, and one character for each column. The card size was exactly 187.325mm by 82.55mm. The cards were made of smooth material, 0.179mm wide. There are about 143 cards for every inch of thickness. In 1964 , IBM switched from square to rounded corners. The 80 column card format dominated the industry, becoming known only as IBM cards, so much so that even other industries had to make cards and the equipment to process them.

Mark sense cards

The Mark sense (electrographic) cards, developed by Reynold B. Johnson at IBM, had printed ovals that could be marked with a special electrographic pencil. The cards could typically be punched with some initial information, such as the name and location of an inventory item. The information to be attached, such as the number of units of the object in mstock, could be marked in the ovals. Card punches with an option to detect mark sense cards could then punch the corresponding information on the card.

Opening cards

Opening cards have a slotted hole on the right side of the punch card. A 35mm piece of microfilm containing a microform image is mounted in the hole. Opening cards are used for engineering diagrams of any engineering discipline. Information about the diagram, for example the drawing number, is typically punched out and printed on the rest of the card. Opening cards have some advantages over digital systems for archiving information

51 column IBM punch card

This IBM punch card format was a shortened 80 column card. Shortening was sometimes done by cutting and removing, at the time of piercing, a piece of an 80 column card. These cards were used in some retail and inventory applications.

IBM Portable Drilling Machine

According to IBM files: The IBM Supply Division introduced the Port-A-Punch in 1958 as a fast and accurate means of punching holes in specially rated IBM punch cards. Designed to carry in a pocket, the portable punch made it possible to create punch card documents anywhere. The product was conceived for “in focus” recording operations – such as physical inventories, job tickets, and statistical surveys – as it eliminated the need for pre-writing or writing source documents. Unfortunately, the resulting holes were “hairy” and sometimes caused problems with the equipment used to read the cards.


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