Donald Knuth writes seven days a week, drafting on a tablet, typing at a standup desk, and writing about five programs weekly. He rewrites constantly for concision, recently integrated a research breakthrough across multiple problems, and watched one book grow from 300 to 350 pages as new ideas emerged.
Questions this video answers
Seven days a week.
About five programs a week.
Supposed to be 300 pages; at the time he said it was up to 350 pages.
"At the end of January" (no year specified in this chunk).
Chapters
So what's your writing process like? What's your thinking and writing process like every day? So what's your routine even?
Yeah, I guess it's actually the best question because I spend seven days a week doing it.
You're the most prepared to answer it.
Yeah, but. Okay, so I. The chair I'm sitting in is where I do.
It's where the magic happens.
Well, reading and writing. The chair is usually sitting over there where I have other book or some reference book. But I found this chair, which was designed by a Swedish guy. Anyway, it turns out this is the only chair I can really sit in for hours and hours and not know that I'm in a chair. But then I have the standup desk right next to us. And so after I write something with pencil, an eraser, I get up and I type it and revise and rewrite standing up.
The kernel of the idea is first put on paper. Yeah, that's where.
Right. And I'll write maybe five programs a week. Of course, literate programming. And these are. Before I describe something in my book, I always program it to see how it's working. And I, and I try it a lot. So, for example, I learned. At the end of January, I learned of a breakthrough by four Japanese people who had extended one of my methods in a new direction. And so I spent the next five days writing a program to implement what they did. And then I, you know, but they had only generalized part of what I had done. So then I had to see if I could generalize more parts of it. And then I had to take their approach and I had to, I had to try it out on a couple of dozen of the other problems I had already worked out with, with my old methods. And so that took another couple of weeks. And then I, you know, then I, then I started to see the light and I, and, and I started writing the final draft and, and then I would, you know, type it up. Involved some new mathematical questions. And so I wrote to my friends and who, who might be good at solving those problems. And, and they solved some, put that in as exercises. And so a month later, I had absorbed one new idea that I learned. And I'm glad I heard about it in time, otherwise I would have put my book out before I'd heard about the idea. On the other hand, this book was supposed to come in at 300 pages, and I'm up to 350 now. That added 10 pages to the book. But if I learn about another one, my publisher is going to shoot me.
Well, so in the process, in that one month process, are some days harder than others?
Are some days harder than others? Well, yeah, my work is fun, but I also work hard and every big job has parts that are a lot more fun than others. And so many days I'll say, why do I have to have such high standards? Why couldn't I just be sloppy and not try this out and just report the answer? But, but I know that people are conning me to do this. And so. Okay, so. Okay, Don, I'll get my teeth and do it. And, and, and then the joy comes out when I see that actually, you know, I'm getting good results. And, and, and I get, and I. Even more when I see that somebody has actually read and understood what I wrote and told me how to make it even better. I did want to mention something about the, about the method. So I got this tablet here where, where I do the first, you know, the first writing of, of concepts. Okay, so, so, and what language is that then? Right, so here you can take a look at it. But, you know, here, random. Say, explain how to draw such skewed pixel diagrams. Okay, so I got this paper about 40 years ago when I was visiting my sister in Canada. And they make tablets of paper with this nice large size and just the.
Right, very small space between life.
Yeah, yeah.
Maybe also just show it.
Yeah, yeah. Wow. You know, I've got these manuscripts going back to the 60s, and those are when I'm getting my ideas on paper. Okay. But I'm a good typist. In fact, I went to typing school when I was in high school. And so I can type faster than I think. So then when I do the editing and stand up and type, then I revise this and it comes out a lot different than what? For style and rhythm and things like that come out at the typing stage.
And you type in tech and I type in tech. And can you, can you think in tech?
No. So to a certain extent I have, I have only a small number of, of idioms that I use. Like, you know, I'm beginning with theorem, I do something for displayed equation, I do something and, and so on. But, but I, I have to see.
It and in the way that it's on paper here.
Yeah. Right.
So, for example, Turing wrote what the other direction, you don't write macros. You don't think in macros.
Not particularly, but when I need a macro, I'll, I'll go ahead and do it. But, but, but the thing is the, I also write to fit I mean, I'll, I'll change something if I can. If I can save a line, I'll, you know, it's like haiku. I'll figure out a way to rewrite the sentence so that it'll look better on the page. And I shouldn't be wasting my time on that, but I can't resist because I know it's only another 3% of the time or something like that.
And it could also be argued that that is what life is about.
Ah yes, in fact that's true. Like I work in the garden one day a week and that's kind of a description of my life is getting rid of weeds, you know, removing bugs for programs.
And so, you know, a lot of writers talk about, you know, basically suffering the writing process as having, you know, it's extremely difficult. And I think of programming, especially the, or technical writing that you're doing can be like that. Do you find yourself methodologically, how do you every day sit down to do the work? Is it a challenge? You kind of say it's, you know, oh yeah, it's fun, but it'd be interesting to hear if there are non fun parts that you really struggle with.
Yeah. So the fun comes when I'm able to put together ideas of two people who didn't know about each other. And so I might be the first person that saw both of their ideas. And so then I get to make the synthesis and that gives me a chance to be creative. But the drudge work is where I've got to chase everything down to its root. This leads me into really interesting stuff. I mean I learn about Sanskrit and I try to give credit to all the authors. And so I write to people who know the people, authors, if they're dead or I communicate this way and I got to get the math right and I got to tackle my programs, try to find holes in them and I rewrite the programs over after I get a better idea.
Is there ever dead ends?
Dead ends? Oh yeah, I throw stuff out. Yeah. One of the things that I spent a lot of time preparing a major example based on the game of baseball. And I know a lot of people who, for whom baseball is the most important thing in the world, you know, but it's, but I also know a lot of people for whom cricket is the most important in the world or soccer or something, you know, and, and I realized that if, if I had a big example, I mean it was going to have a fold out illustration and everything I would say, well, what, what am I really teaching about algorithms here, where I had this, this, this, this baseball example. And if I was a person who, who know, who knew only cricket, wouldn't they, what would they think about this? And so, so I've ripped, you know, I had, I had a, something that would have really appealed to people who grew up with baseball as a major theme in their life, which is a.
Lot of people, but still a minority, small minority.
