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 faste

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.