Knuth reward check
Categories: Prizes | TeX
Donald Knuth, in the preface of each of his books, and also on his website, offers to cheerfully pay a reward of $2.56 to the first finder of each error, whether it be technical, typographical, or historical. For those who have to ask, his FAQ explains that "256 pennies is one hexadecimal dollar". An article in MIT's Technology Review describes these reward checks as "among computerdom's most prized trophies" [1]. As of October 2001, Knuth reports having written more than 2,000 such checks, with an average value exceeding $8 per check [2]. The "History of TeX" explains that "Knuth's name is so valued that very few of his checks — even the largest ones — are actually cashed, but instead framed." [3]
The reward for coding errors found in Knuth's TEX and METAFONT programs (as distinguished from errors in Knuth's books) followed an audacious scheme inspired by the Wheat and Chessboard Problem [4]. It started at $2.56, and doubled every year until it reached $327.68[5]. Recipients of this "sweepstakes" reward include Chris Thompson (Cambridge) and Boguslaw Jackowski (Gdansk) [6].
- Intelligence: Finding an error in a Knuth text.
- Stupidity: Cashing that $2.56 check you got.
- Seen in a Slashdot sig, quoted by Edward O'Connor [7]
Each check's memo field identifies the book and page number. 1.23 indicates an error on page 23 of Volume 1. (1.23) indicates a valuable suggestion on that page. Such suggestions are worth 32¢ each. Note: Θ denotes the book Things a Computer Scientist Rarely Talks About, KLR denotes the book Mathematical Writing (by Knuth, Larrabee, and Roberts), GKP denotes the book Concrete Mathematics (by Graham, Knuth, and Patashnik), and f1 denotes fascicle 1.
| chk# | date | amount | book | name/check-image (external) |
|---|---|---|---|---|
| 1384 | 1989-10-30 | $2.56 | TeX | Richard J. Kinch |
| 289 | 1997-12-31 | $2.56 | 1 | Sean T. Barrett |
| 333 | 1998-02-26 | $2.56 | 2 | Michael Driscoll |
| 428 | 1998-08-10 | $2.56 | A | Gabriel Valiente |
| 430 | 1998-08-10 | $2.88 | 3 | Sean T. Barrett |
| 628 | 1999-12-24 | $8.71 | SGB | Gabriel Valiente |
| 747 | 2001-01-01 | $2.56 | CS | Gabriel Valiente |
| 913 | 2002-01-09 | $2.56 | Θ | Indrayana (Indra) Rustandi |
| 1015 | 2002-08-24 | $2.56 | KLR | Gabriel Valiente |
| 1048 | 2002-11-27 | $2.56 | 1 | Amit Singh |
| 1124 | 2003-08-29 | $2.56 | GKP | Mariano Suárez-Alvarez |
| 151 | 2004-10-22 | $2.56 | f1 | [David Eger] |
Frank Ruskey's class with checks
Some reward checks include interest compounded continuously (PostScript file).
On July 1, 1996, Knuth sent out more than 250 letters, 125 of which contained checks, for errors reported in The Art of Computer Programming since the summer of 1981. A few of these remain unclaimed [8].
External links
- Interview (RealVideo format) with Knuth on National Public Radio