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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 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 ...
The IBM card readers 3504, 3505 and the multifunction unit 3525 used a different encoding scheme for column binary data, also known as card image, where each column, split into two rows of 6 (12–3 and 4–9) was encoded into two 8-bit bytes, holes in each group represented by bits 2 to 7 (MSb numbering, bit 0 and 1 unused ) in successive ...
The 711's read mechanism was based on the IBM 402's and could read 150 cards per minute (250 cards per minute on the IBM 7090). It included a control panel that could be wired to transfer any 72 columns out of the 80 on a card into the computer's memory, though in practice the panel was almost always wired to read the first 72 columns.
IBM 1442 [1] [2] is a combination IBM card reader and card punch. It reads and punches 80-column IBM-format punched cards [ 3 ] and is used on the IBM 1440 , the IBM 1130 , the IBM 1800 [ 4 ] and System/360 [ 5 ] and is an option on the IBM System/3 .
Card punch speed up to 250 cards per minute (all models). Feed hopper for 1,200 cards (all models). Three stackers (NP, 4, 2/8) of approximately 1,000-card capacity after cards are punched. The 2/8 stacker is shared by the card reader and punch, but timing considerations make it difficult to use for merging operations.
The IBM 2501 is a punched-card reader from IBM with models for the System/360 and System/370 mainframe systems and for the IBM System/360 Model 20, the IBM 1130 and IBM System/3 minicomputers. 2501 models can read 80-column cards at either 600 or 1000 cards per minute (CPM).
The card reader made things easier because it had a special Load button to signify that the first card was to be read into the computer's memory (starting at address 00000) and executed (as opposed to just starting the card reader, which then awaits commands from the computer to read cards) – this is the "bootstrap" process that gets into the ...