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It's a little off-putting that he says punched paper tape was used in the early days of computing. Mostly it was punched paper cards, a different thing entirel

by mark-r 3y ago

It's a little off-putting that he says punched paper tape was used in the early days of computing. Mostly it was punched paper cards, a different thing entirely.

HarHarVeryFunny 3y ago
Well, there were both. Punched cards were used in computing centers for preparing batch mainframe jobs for submission. Punched tape was more a hobbyist thing, as form of program storage and sharing, used in the era of early machines such as the Altair 8800. You can still buy a copy of Microsoft BASIC on punched tape if you need it! https://www.ebay.com/itm/196212300301 https://www.ebay.com/itm/196212300301
- mbreese 3y ago
  To add to your comment… I thought the use of paper tape was directly related to the teletypes (when used for I/O with a computer). Where the paper tape could operate as both an input and output mechanism, depending on if you wanted to input a program/text or save a program/text. Paper tape wasn’t a computer storage medium, as much as it was a teletype medium. In this way, the paper tape hijacked the interactive I/O mode on these early computers to supplant it with a stored format.
  - nomadluap 3y ago
    I guess you could look at paper tape as a physical manifestation of redirecting terminal I/O to text files using > and < in the shell.
  - HarHarVeryFunny 3y ago
    Interesting - I wasn't aware of that. When I first learnt to program (in PL/1) in the 70's it was on a punched card system, but I never used paper tape myself. So, was switching from keyboard to tape input, or from printer to tape output, done locally at the teletype, or could that be controlled by the computer it was attached to ? I guess this implies the paper tape format was basically just a dump/listing of sorts that might otherwise have been directed to the printer, and when used as an input this would then be read into a program (e.g. editor) that was really expecting keyboard (tty) input ?
    - mark-r 3y ago
      You could turn on the paper tape punch at any time, and it would record every character sent to the printer. Then you could load the tape into the reader and turn it on and it would act as if you were typing at maximum speed (a whole 10 characters per second!) I don't recall any way to control either function remotely.
- mark-r 3y ago
  Yes, in the early days of microcomputers teletypes were common, and paper tape was a part of that. I'm talking about the computers of the 1960's for example where interactive use was unheard of.
jcrawfordor 3y ago
It's not at all a clean separation, but in early computers, paper tape is more common for loading programs than punched cards. The paper tape readers were faster, and the flexible length made more sense for software before compilers were involved. Punched cards were mostly used for application input/output (a very early example would be ENIAC which was not stored-program at all but had punched card I/O) where fixed record sizes made sense, and then later for software due to FORTRAN and contemporaries introducing well-defined statements. Of course there are plenty of exceptions. I mostly left out punched cards because they have a completely different pre-computer history that could take its own article. One of the reasons people perceive punched cards as far more common than paper tape is because IBM used them heavily (although early IBM machines still tended to use paper tape for loading software). IBM used them heavily because IBM had already been manufacturing punched card equipment for pre-computer data processing. But that's also why early IBM computers supported punched card I/O: for interoperation with their data processing systems. For example, early IBM computers from the '50s even to relatively modern machines in the '70s were often used alongside older punched card data processing equipment. You might categorize records using a punched-card sorter and then feed the sorter bins into a computer for computing statistics, then take the cards output by the computer and put them into a punched card sorter again to order by the computed statistics. This is how might you produce a report of counties with the highest sales, for example. A hybrid of computer and pre-computer methods of processing data. But this emphasizes the difference between paper tape and punched cards: paper tape was continuous, good for variable-length material. Punched cards were discrete, good for fixed-size records that would be binned and sorted during processing. Later the adoption of IBM punched cards for compiler input radically changed this situation, but that still came out of the sense that input to the compiler consisted of well-defined, discrete records identified by serial number. You can imagine the practicalities. Machine-language software would not fit neatly onto punched card boundaries, the length of punched cards being historic and not well-correlated with the word size on machines. So there's a weird alignment problem you get that paper tape avoids. Plus you can't accidentally reorder paper tape, an advantage that paper tape equipment manufacturers actively advertised! A major example relevant to the article is Digital - DEC PDP machines used paper tape for program loading and were rarely equipped for punched cards. This reflects their different heritage and market from IBM machines; Digital machines were less common (and not really designed for) batch record processing applications. Punched cards, on the other hand, are almost intrinsically a batched record format.

by mark-r 3y ago

It's a little off-putting that he says punched paper tape was used in the early days of computing. Mostly it was punched paper cards, a different thing entirely.

HarHarVeryFunny 3y ago

Well, there were both. Punched cards were used in computing centers for preparing batch mainframe jobs for submission. Punched tape was more a hobbyist thing, as form of program storage and sharing, used in the era of early machines such as the Altair 8800. You can still buy a copy of Microsoft BASIC on punched tape if you need it! https://www.ebay.com/itm/196212300301 https://www.ebay.com/itm/196212300301

mbreese 3y ago
To add to your comment… I thought the use of paper tape was directly related to the teletypes (when used for I/O with a computer). Where the paper tape could operate as both an input and output mechanism, depending on if you wanted to input a program/text or save a program/text. Paper tape wasn’t a computer storage medium, as much as it was a teletype medium. In this way, the paper tape hijacked the interactive I/O mode on these early computers to supplant it with a stored format.
- nomadluap 3y ago
  I guess you could look at paper tape as a physical manifestation of redirecting terminal I/O to text files using > and < in the shell.
- HarHarVeryFunny 3y ago
  Interesting - I wasn't aware of that. When I first learnt to program (in PL/1) in the 70's it was on a punched card system, but I never used paper tape myself. So, was switching from keyboard to tape input, or from printer to tape output, done locally at the teletype, or could that be controlled by the computer it was attached to ? I guess this implies the paper tape format was basically just a dump/listing of sorts that might otherwise have been directed to the printer, and when used as an input this would then be read into a program (e.g. editor) that was really expecting keyboard (tty) input ?
  - mark-r 3y ago
    You could turn on the paper tape punch at any time, and it would record every character sent to the printer. Then you could load the tape into the reader and turn it on and it would act as if you were typing at maximum speed (a whole 10 characters per second!) I don't recall any way to control either function remotely.
mark-r 3y ago
Yes, in the early days of microcomputers teletypes were common, and paper tape was a part of that. I'm talking about the computers of the 1960's for example where interactive use was unheard of.

jcrawfordor 3y ago

It's not at all a clean separation, but in early computers, paper tape is more common for loading programs than punched cards. The paper tape readers were faster, and the flexible length made more sense for software before compilers were involved. Punched cards were mostly used for application input/output (a very early example would be ENIAC which was not stored-program at all but had punched card I/O) where fixed record sizes made sense, and then later for software due to FORTRAN and contemporaries introducing well-defined statements. Of course there are plenty of exceptions. I mostly left out punched cards because they have a completely different pre-computer history that could take its own article. One of the reasons people perceive punched cards as far more common than paper tape is because IBM used them heavily (although early IBM machines still tended to use paper tape for loading software). IBM used them heavily because IBM had already been manufacturing punched card equipment for pre-computer data processing. But that's also why early IBM computers supported punched card I/O: for interoperation with their data processing systems. For example, early IBM computers from the '50s even to relatively modern machines in the '70s were often used alongside older punched card data processing equipment. You might categorize records using a punched-card sorter and then feed the sorter bins into a computer for computing statistics, then take the cards output by the computer and put them into a punched card sorter again to order by the computed statistics. This is how might you produce a report of counties with the highest sales, for example. A hybrid of computer and pre-computer methods of processing data. But this emphasizes the difference between paper tape and punched cards: paper tape was continuous, good for variable-length material. Punched cards were discrete, good for fixed-size records that would be binned and sorted during processing. Later the adoption of IBM punched cards for compiler input radically changed this situation, but that still came out of the sense that input to the compiler consisted of well-defined, discrete records identified by serial number. You can imagine the practicalities. Machine-language software would not fit neatly onto punched card boundaries, the length of punched cards being historic and not well-correlated with the word size on machines. So there's a weird alignment problem you get that paper tape avoids. Plus you can't accidentally reorder paper tape, an advantage that paper tape equipment manufacturers actively advertised! A major example relevant to the article is Digital - DEC PDP machines used paper tape for program loading and were rarely equipped for punched cards. This reflects their different heritage and market from IBM machines; Digital machines were less common (and not really designed for) batch record processing applications. Punched cards, on the other hand, are almost intrinsically a batched record format.