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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.
A 12-row/80-column IBM punched card from the mid-twentieth century. A punched card (also punch card [1] or punched-card [2]) is a piece of card stock that stores digital data using punched holes. Punched cards were once common in data processing and the control of automated machines.
It is called an overpunch because the digit in that column has a 12-punch or an 11-punch above it to indicate the sign. The top three rows of the card are called zone punches , [ 3 ] and so numeric character data which may contain overpunches is called zoned decimal .
This category contains articles about punched cards and card handling equipment, including card readers, card punches, and keypunches. Subcategories This category has the following 2 subcategories, out of 2 total.
Numeric columns have one punch in rows 0-9, possibly a sign overpunch in rows 11-12, and can be sorted in a single pass through the sorter. Alphabetic columns have a zone punch in rows 12, 11, or 0 and a digit punch in one of the rows 1-9, and can be sorted by passing some or all of the cards through the sorter twice on that column.
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 ...
Columns on different punch cards vary from 5 to 12 punch positions. The method used to store data on punched cards is vendor specific. In general each column represents a single digit, letter or special character. Sequential card columns allocated for a specific use, such as names, addresses, multi-digit numbers, etc., are known as a field.
The 1442 Model 2 reads cards at 400 cpm and punches from 91 to 360 cpm. Two stackers are standard. The 1442 Model 6 attaches to an IBM System/3 or IBM 1130, reads 300 cpm [11] and punches 80 columns per second. [12] The 1442 Model 7 attaches to an IBM System/3 or IBM 1130, reads 400 cpm and punches 180 columns per second.