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Description of Photograph

This IBM card format, designed in 1928, had rectangular holes, 80 columns with 12 punch locations each, one character to each column. Card size was exactly 7-3/8 inch by 3-1/4 inch (187.325 by 82.55 mm). The cards were made of smooth stock, 0.007 inch (0.178 mm) thick. There are about 143 cards to the inch. In 1964, IBM changed from square to round corners.
The lower ten positions represented (from top to bottom) the digits 0 through 9. The top two positions of a column were called zone punches, 12 (top) and 11. Originally only numeric information was coded, with 1 punch per column indicating the digit. Signs could be added to a field by overpunching the least significant digit with a zone punch: 12 for plus and 11 for minus. Zone punches had other uses in processing as well, such as indicating a master record.
 
The card illustrated was used in our Phillips P354 Visible Card Reader
 
 
 

Date: Unknown



Comment on This Photograph

This exhibit has a reference ID of CH1425. Please quote this reference ID in any communication with the Centre for Computing History.

Photograph of 80 Column Punch Card

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