Written language is the easiest of all, because, of course, it consists of strings of symbols to begin with. If the symbols happen to belong to a phonetic alphabet (as opposed to, say, ideograms), converting them into bits is a trivial procedure, and one that was nailed, technologically, in the early nineteenth century, with the introduction of Morse code and other forms of telegraphy.

We had a human/computer interface a hundred years before we had computers. When computers came into being around the time of the Second World War, humans, quite naturally, communicated with them by simply grafting them on to the already-existing technologies for translating letters into bits and vice versa: teletypes and punch card machines.

These embodied two fundamentally different approaches to computing. When you were using cards, you'd punch a whole stack of them and run them through the reader all at once, which was called batch processing. You could also do batch processing with a teletype, as I have already described, by using the paper tape reader, and we were certainly encouraged to use this approach when I was in high school. But--though efforts were made to keep us unaware of this--the teletype could do something that the card reader could not. On the teletype, once the modem link was established, you could just type in a line and hit the return key. The teletype would send that line to the computer, which might or might not respond with some lines of its own, which the teletype would hammer out--producing, over time, a transcript of your exchange with the machine. This way of doing it did not even have a name at the time, but when, much later, an alternative became available, it was retroactively dubbed the Command Line Interface.

When I moved on to college, I did my computing in large, stifling rooms where scores of students would sit in front of slightly updated versions of the same machines and write computer programs: these used dot-matrix printing mechanisms, but were (from the computer's point of view) identical to the old teletypes.



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