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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Who introduced the standard 8-bit punched tape, and when?

Who introduced the standard that later became widespread for the 8-bit punch tape, and when? I think the 5-bit tape was an earlier standard.
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How were 18-bit instructions encoded in paper tape?

Early 18-bit computers like PDP-1 were based on 18-bit instruction sets, and used punched paper tape for storage etc. As far as I know paper tape was usually 8 holes, which works nicely with 16-bit ...
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What was the use case for the 96-column punch cards introduced with the IBM System/3?

Shown here at the Computer History Museum site (*) Not sure when they were introduced but it was before optical scanning (barcodes) was possible / affordable, maybe even before magnetic stripe ...
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What does this 1970s punched-card format mean?

The 1974 Texas Regional Programming Contest (a predecessor of the ICPC) describes an input format: A room description will be contained on a single card with the format: (1X, I2, 2X, 12 (A1, I2, 2X))....
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How were card sequence numbers typically checked?

Although average punched cards had eighty columns, often only seventy-two were used for characters; the remaining eight were ignored by software. Hence arbitrary metadata could be included with each ...
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Why ASCII paper tape has lower bit punched from the narrow side?

ASCII was presented on paper tape where the lower 5 bits cross sprocket holes as following While FIELDATA chose the other way I found placing the higher, flag bits at the narrow side appealing, ...
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Could early computers use existing punch card machines?

In the early decades of the industry, computers used punch cards for data storage and transmission, partly because they were already widely used for pre-computer data processing; indeed, a major ...
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Why were programs entered on punch cards instead of paper tapes?

Dale Fisk's Programming With Punched Cards is a fascinating account of programming in the days of punch cards. The fundamental dynamic was that early computers did not yet support timesharing. The ...
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Was there a way to directly print out a deck of punch cards without involving a computer?

Was there any equipment which could directly print out the program or data on a stack of punchcards, without first loading the deck into a general-purpose computer? In other words, a transfer from the ...
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How much data could be stored on a single punched card?

I was looking at this IBM webpage on the history of floppy disks and it says the original 8-inch floppy disk from 1971 could store 80 KB of data, equivalent to that of 3000 punched cards. So, based on ...
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Were punch-card data-processing systems susceptible to "Bobby Tables"

At least in the U.S., during the 1970s and 1980s (and likely before), many tollways and other ticket-based systems used to use publicly distributed and collected "IBM-style" punched cards ...
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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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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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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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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 ...
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8 answers
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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 ...
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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 ...
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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 ...
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3 votes
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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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8 votes
3 answers
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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 ...
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8 votes
4 answers
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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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14 votes
3 answers
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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 ...
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