Questions tagged [punched-cards]

Punched cards were an early method of digital computer data storage, using cards made of stiff paper with holes punched in specific locations to represent data. They could be punched manually or automatically, were generally read automatically, and commonly held up to a few hundred bytes of data each.

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11
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4answers
3k views

Were round punchcard holes mechanically stiffer?

The most common punch card format was the IBM 80 column by 12 row, with narrow rectangular holes. However, there were other possibilities, such as a later IBM format that used round holes. That one ...
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5answers
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What did code on punch cards do with the other six bits per column?

In the fifties and sixties, program source code was typically stored on punch cards, one card per line. The most common card format was the IBM 80 column by 12 row. For source code, this was commonly ...
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1answer
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What was the DEC CR11 card reader 'compressed Hollerith code' for?

In this manual for the DEC CR11 card reader controller, the controller can deliver the card content to the PDP11 in either of two forms: Column binary: the 12 rows of hole/no-hole are delivered in ...
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5answers
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How binaries are generated using Punched cards? [duplicate]

I thought that punched cards already represent the code in binary since a hole means 0 and rest positions mean 1 on a punched card. But then I read that you could use punched cards to present the ...
21
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8answers
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Do the holes in Jacquard loom punched cards represent input data or program code?

I think they represent data because I feel it is a mechanical machine which is fully configured and the holes decide only that the thread related to each hole must be moved or not. Thus the holes ...
4
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2answers
246 views

How did IBM's “Mag Card” drive and magnetic media work?

In the 1970's IBM popularized an early word processing solution using their popular Selectric typewriter line and something called "Mag Card". This video demonstrates the system in operation. The ...
3
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1answer
135 views

What was the first company to sell an IBM compatible punchcard reader?

Punchcards were the primary way to get information into computers up through the sixties. The familiar eighty column format was designed by IBM, and was a factor in the later de facto standard eighty ...
3
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4answers
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What do the numbers on the punch cards mean?

Does anyone know what is the meaning of the numbers in punch cards? I need an example of any language, it's important for me to understand which information could be manipulated.
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Non-Computer Punch-Card Systems other than Edge-Notched Cards

Caveat: This is maybe a borderline for RC, as it's about systematic data processing even before (and in parallel to) computers. Before (and parallel to) computer and/or tabulating machine punch cards ...
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Why are punch card readers no longer in use?

When you think about it, punch cards are the safest way to backup data for long term storage. They are not influenced by magnetic fields and their data (the holes) don't fade over time. They are also ...
8
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714 views

How did a punchcard-based test-taking system work?

A punchcard (in 3 fragments) has been found in a copy of Computer Programming: A Mixed Language Approach by Marvin L. Stein and William D. Munro (1965). If my guess is right, a test-taker would write ...
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3answers
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Which programming systems used object files on punch cards?

In a batch programming system developed in the late 1960s - early 1970s at the Joint Institute for Nuclear Research in the city of Dubna near Moscow, it was possible to dump object files to punch ...