Seibel: Do you feel like programmers and computer scientists are aware enough of the history of our field? It is, after all, a pretty short history.

Knuth: There aren’t too many that are scholars. Even when I started writing my books in 1963, I didn’t think people knew what had happened in 1959 I was reading in American Scientist last week about people who had rediscovered an algorithm that Boyer and Moore had discovered in 1980. It happens all the time that people don’t realize the glorious history that we have. The idea that people knew a thing or two in the ’70s is strange to a lot of young programmers.

It’s inevitable that in such a complicated field that people will be missing stuff. Hopefully with things like Wikipedia, achievements don’t get forgotten the way they were before. But I wish I could also instill in more people the love that I have for reading original sources. Not just knowing that so-and-so gets credit for doing something, but looking back and seeing what that person said in his own words. I think it’s a tremendous way to improve your own skills.

It’s very important to be able to get inside of somebody else’s way of thinking, to decode their vocabulary, their notation. If you can understand something about the way they thought and the way they made a discovery, then that helps you make your own discoveries. I often read source materials of what brilliant people have said about this stuff in the past. It’ll be expressed in unusual ways by today’s conventions, but it’s worth it to me to penetrate their notation and to try to get into their idea.

For example I spent a good deal of time trying to look at Babylonian manuscripts of how they described algorithms 4,000 years ago, and what did they think about? Did they have while loops and stuff like this? How would they describe it? And to me this was very worthwhile for understanding
about how the brain works, but also about how they discovered things.

A couple of years ago I found an old Sanskrit document from the 13th century that was about combinatorial math. Almost nobody the author knew would have had the foggiest idea what he was talking about. But I found a translation of this document and it was speaking to me. I had done
similar kinds of thinking when I was beginning in computer programming.

And so to me reading source materials is great enrichment for my own life and creativity. I was unable to pass that on to any of my students. There are people alive now in computer science who are doing this well—a few. But I could count on the fingers of one hand the people who love source materials the way I do.

I’ve got lots of collections of source code. I have compilers, the Digitek compilers from the 1960s were written in a very interesting way. They had their own language and they used identifiers that were 30 characters long but very descriptive, and their compilers ran circles around the competition
at the time—this company made the state-of-the-art compilers of 1963 or ’64.

And I’ve got Dijkstra’s source code for the THE operating system. I haven’t read that. I’ve just skimmed it so far but I collected it because I’m sure it would be interesting to read if I had time.

One time I broke my arm—fell off a bike—and I had a month where I couldn’t do anything much, so I read source code that I had heard had some clever ideas in it that hadn’t been documented. I think those were all extremely important experiences for me.

Coders at Work – Page 600 – Donald Knuth