Perhaps the most enjoyable emotion, however, was the sense of personal fulfillment. When it came to hacking, Stallman was a natural. A childhood’s worth of late-night study sessions gave him the ability to work long hours with little sleep. As a social outcast since age 10, he had little difficulty working alone. And as a mathematician with built-in gift for logic and foresight, Stallman possessed the ability to circumvent design barriers that left most hackers spinning their wheels.
“He was special”, recalls Gerald Sussman, an MIT faculty member and former AI Lab researcher. Describing Stallman as a “clear thinker and a clear designer”, Sussman employed Stallman as a research-project assistant beginning in 1975. The project was complex, involving the creation of an AI program that could analyze circuit diagrams. Not only did it involve an expert’s command of Lisp, a programming language built specifically for AI applications, but it also required an understanding of how a human might approach the same task.
When he wasn’t working on official projects such as Sussman’s automated circuit-analysis program, Stallman devoted his time to pet projects. It was in a hacker’s best interest to improve the lab’s software infrastructure, and one of Stallman’s biggest pet projects during this period was the lab’s editor program TECO.
The story of Stallman’s work on TECO during the 1970s is inextricably linked with Stallman’s later leadership of the free software movement. It is also a significant stage in the history of computer evolution, so much so that a brief recapitulation of that evolution is necessary. During the 1950s and 1960s, when computers were first appearing at universities, computer programming was an incredibly abstract pursuit. To communicate with the machine, programmers created a series of punch cards, with each card representing an individual software command. Programmers would then hand the cards over to a central system administrator who would then insert them, one by one, into the machine, waiting for the machine to spit out a new set of punch cards, which the programmer would then decipher as output. This process, known as “batch processing”, was cumbersome and time consuming. It was also prone to abuses of authority. One of the motivating factors behind hackers’ inbred aversion to centralization was the power held by early system operators in dictating which jobs held top priority.
In 1962, computer scientists and hackers involved in MIT’s Project MAC, an early forerunner of the AI Lab, took steps to alleviate this frustration. Time-sharing, originally known as “time stealing”, made it possible for multiple programs to take advantage of a machine’s operational capabilities. Teletype interfaces also made it possible to communicate with a machine not through a series of punched holes but through actual text. A programmer typed in commands and read the line-by-line output generated by the machine.
During the late 1960s, interface design made additional leaps. In a famous 1968 lecture, Doug Engelbart, a scientist then working at the Stanford Research Institute, unveiled a prototype of the modern graphical interface. Rigging up a television set to the computer and adding a pointer device which Engelbart dubbed a “mouse”, the scientist created a system even more interactive than the time-sharing system developed a MIT. Treating the video display like a high-speed printer, Engelbart’s system gave a user the ability to move the cursor around the screen and see the cursor position updated by the computer in real time. The user suddenly had the ability to position text anywhere on the screen.
Such innovations would take another two decades to make their way into the commercial marketplace. Still, by the 1970s, video screens had started to replace teletypes as display terminals, creating the potential for full-screen-as opposed to line-by-line-editing capabilities.
One of the first programs to take advantage of this full-screen capability was the MIT AI Lab’s TECO. Short for Text Editor and COrrector, the program had been upgraded by hackers from an old teletype line editor for the lab’s PDP-6 machine.[4]
TECO was a substantial improvement over old editors, but it still had its drawbacks. To create and edit a document, a programmer had to enter a series of software commands specifying each edit. It was an abstract process. Unlike modern word processors, which update text with each keystroke, TECO demanded that the user enter an extended series of editing instructions followed by an “end of command” sequence just to change the text.Over time, a hacker grew proficient enough to write entire documents in edit mode, but as Stallman himself would later point out, the process required “a mental skill like that of blindfold chess”.[5]
To facilitate the process, AI Lab hackers had built a system that displayed both the “source” and “display” modes on a split screen. Despite this innovative hack, switching from mode to mode was still a nuisance.
TECO wasn’t the only full-screen editor floating around the computer world at this time. During a visit to the Stanford Artificial Intelligence Lab in 1976, Stallman encountered an edit program named E. The program contained an internal feature, which allowed a user to update display text after each command keystroke. In the language of 1970s programming, E was one of the first rudimentary WYSIWYG editors. Short for “what you see is what you get”, WYSIWYG meant that a user could manipulate the file by moving through the displayed text, as opposed to working through a back-end editor program.[6]
Impressed by the hack, Stallman looked for ways to expand TECO’s functionality in similar fashion upon his return to MIT. He found a TECO feature called Control-R, written by Carl Mikkelson and named after the two-key combination that triggered it. Mikkelson’s hack switched TECO from its usual abstract command-execution mode to a more intuitive keystroke-by-keystroke mode. Stallman revised the feature in a subtle but significant way. He made it possible to trigger other TECO command strings, or “macros”, using other, two-key combinations. Where users had once entered command strings and discarded them after entering then, Stallman’s hack made it possible to save macro tricks on file and call them up at will. Mikkelson’s hack had raised TECO to the level of a WYSIWYG editor. Stallman’s hack had raised it to the level of a user-programmable WYSIWYG editor. “That was the real breakthrough”, says Guy Steele, a fellow AI Lab hacker at the time.[6]
By Stallman’s own recollection, the macro hack touched off an explosion of further innovation. “Everybody and his brother was writing his own collection of redefined screen-editor commands, a command for everything he typically liked to do”, Stallman would later recall. “People would pass them around and improve them, making them more powerful and more general. The collections of redefinitions gradually became system programs in their own right”.[6]
So many people found the macro innovations useful and had incorporated it into their own TECO programs that the TECO editor had become secondary to the macro mania it inspired. “We started to categorize it mentally as a programming language rather than as an editor”, Stallman says. Users were experiencing their own pleasure tweaking the software and trading new ideas.[6]
Two years after the explosion, the rate of innovation began to exhibit dangerous side effects. The explosive growth had provided an exciting validation of the collaborative hacker approach, but it had also led to over-complexity. “We had a Tower of Babel effect”, says Guy Steele.
The effect threatened to kill the spirit that had created it, Steele says. Hackers had designed ITS to facilitate programmers’ ability to share knowledge and improve each other’s work. That meant being able to sit down at another programmer’s desk, open up a programmer’s work and make comments and modifications directly within the software. “Sometimes the easiest way to show somebody how to program or debug something was simply to sit down at the terminal and do it for them”, explains Steele.
4.
According to the Jargon File, TECO’s name originally stood for Tape Editor and Corrector.
http://www.tuxedo.org/~esr/jargon/html/entry/TECO.html
5.
See Richard Stallman, “EMACS: The Extensible, Customizable, Display Editor”, AI Lab Memo (1979). An updated HTML version of this memo, from which I am quoting, is available at