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Why the designer and the implementer of a program should be the same person


Working on TeX
Donald Knuth Scientist
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I started programming in a… in a way that I hadn't done before. During the '70s, a…a style of programming was developed called structured programming, which… which made it easier… easier to… to produce reliable programs… programs that you could understand as you were writing them.  And… and… and I had done some experiments with it on a lower – on a smaller – scale, but this was going to be my first large program written with this methodology of structured programming. And the… the new thing was that as I'm writing the program, I didn't feel the need to test it… to test each part of it as I was writing it. I… I could… I could just write and write and write and… and assume that after it's all written, it'll be pretty close to working. So what actually happened is that I… I started writing in September or October, and I didn't test… I… I didn't actually enter any of the program into the computer or test it or… or debug it until the next March.  So all these months are going by, and… and I… I didn't feel the need for a prototype or any… any… I mean, the way most programmers write something is they'll… they’ll put… they'll put something together and then that's only part of the program so then they'll mock up the missing parts to have something that pretends that these other missing parts are… are there before they write them, but then… then later on when those parts are there, then they can… they can continue, and so… and they… and they build up more confidence all the time. Well, with structured programming I already had pretty much confidence, so I didn't feel the need to dummy up these… these extra parts, and that saved me a lot of time because all the time that I would take to… to write… to write the dummies, I… I no longer… no longer needed. But, sometimes I have to admit a… a few twinges of doubt, you know, you had 5 months are going by between the time I wrote the… the program to… to the time I'd get to really try it out, but you see, I couldn't… I… One of the things I would have had to dummy up was the whole… the whole question of fonts. I… I couldn't do typesetting without the fonts, and… and I had… I had to write those… I had to do all those fonts as well, and that was, you know, 3… 3 months of that 5 was to… was to get the fonts going.

Born in 1938, American computing pioneer Donald Knuth is known for his greatly influential multi-volume work, 'The Art of Computer Programming', his novel 'Surreal Numbers', his invention of TeX and METAFONT electronic publishing tools and his quirky sense of humor.

Listeners: Dikran Karagueuzian

Trained as a journalist, Dikran Karagueuzian is the director of CSLI Publications, publisher of seven books by Donald Knuth. He has known Knuth since the late seventies when Knuth was developing TeX and Metafont, the typesetting and type designing computer programs, respectively.

Tags: structured programming

Duration: 2 minutes, 37 seconds

Date story recorded: April 2006

Date story went live: 24 January 2008