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The IBM 421 accounting machine saw use in the 1960s. The largely-mechanical IBM 421 read 80-column punch cards and could print upper-case letters of the alphabet, the decimal digits 0 to 9, a period (.), and plus and minus signs. The operation of the 421 was directed by the use of a removable control panel and a carriage tape. By means of the ...
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 ...
Punched cards were once common in data processing and the control of automated machines. Punched cards were widely used in the 20th century, where unit record machines, organized into data processing systems, used punched cards for data input, output, and storage. [3] [4] The IBM 12-row/80-column punched card format came to dominate the industry.
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.
Cards with a particular punch could be treated as master cards causing different behavior. For example, customer master cards could be merged with sorted cards recording individual items purchased. When read by the tabulating machine to create invoices, the billing address and customer number would be printed from the master card, and then ...
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.
The IBM 601 Multiplying Punch was a unit record machine that could read two numbers from a punched card and punch their product in a blank field on the same card. The factors could be up to eight decimal digits long. [ 1 ]
Powers-Samas machines detected the holes in punched cards mechanically, unlike IBM equipment where holes in punched cards are detected by electrical circuits. Pins that could drop through round holes in punched cards were connected to linkages and their displacement when a hole was present actuated other parts of the machine to produce the desired results.