As word spread and more users took advantage of his free software (written for an academic mainframe computer but soon made available for PCs), Knuth found himself studying the history of printing to find solutions for narrow applications. Often as not, his research proved fruitless and he would have to come up with his own answer. For ceremonial invitations, he created new fonts; for musical typesetting he solved difficult alignment problems. “I had so many users,” he recalls. “From wedding invitations and programs for the local symphonic orchestra to computer programs.”
For nearly nine years, Knuth’s foray into typography occupied him full time-pulling him away from work on the programming book that he considered his true calling. “I had to think of the endgame,” he says. “How could I responsibly finish TeX and say: This is not going to change anymore? I had to work out a four-year strategy to extricate myself” and return to The Art of Computer Programming.
Knuth’s solution: with the release of TeX version 3.0 in 1990, he declared his work complete. Disciples will have to maintain the system. Knuth says he will limit his work to repairing the rare bugs brought to his attention; with each fix he assigns one more digit to the version number so that it tends to pi (the current version is 3.14159).
One result of Knuth’s decision to stop making major changes to TeX is that the TeX file format has remained unchanged. “It’s the only software where you can take the file for your paper from 1985 and not have to convert it to print out the same way today,” notes David Fuchs, a senior researcher with Liberate Technologies (formerly Network Computer Inc.),who was a grad student at Stanford during the development of TeX. Fuchs estimates that there are 1 million TeX users worldwide; many employ special-purpose commercial packages built around the TeX “kernel,” such as LATeX (a command-oriented macro language) and TeXDoc (optimized for software documentation).
“On the downside, TeX is limited in its appeal because it’s not WYSIWYG,” Fuchs admits, employing the acronym for “what you see is what you get”-the standard term describing text processing software that displays formatting on screen as it will appear on the printed page. Rather than offering real-time onscreen interactivity, TeX requires a markup language typed into a document and interpreted by the computer; you see what you get only after it is in print. Despite its unintuitive user interface, TeX has developed a dedicated core of production professionals who will accept no substitute. “Why would anyone want anything else?” asks Paul Anagnostopolis, a Carlisle, Mass.-based publishers’ consultant and author of TeX-based software for book composition. “A lot of people don’t care about WYSIWYG.”