Stallman quickly learned that the AI Lab’s first-come, first-served policy owed much to the efforts of a vigilant few. Many were holdovers from the days of Project MAC, the Department of Defense-funded research program that had given birth to the first time-share operating systems. A few were already legends in the computing world. There was Richard Greenblatt, the lab’s in-house Lisp expert and author of MacHack, the computer chess program that had once humbled A.I. critic Hubert Dreyfus. There was Gerald Sussman, original author of the robotic block-stacking program HACKER. And there was Bill Gosper, the in-house math whiz already in the midst of an 18-month hacking bender triggered by the philosophical implications of the computer game LIFE.[4]
Members of the tight-knit group called themselves “hackers”. Over time, they extended the “hacker” description to Stallman as well. In the process of doing so, they inculcated Stallman in the ethical traditions of the “hacker ethic”. To be a hacker meant more than just writing programs, Stallman learned. It meant writing the best possible programs. It meant sitting at a terminal for 36 hours straight if that’s what it took to write the best possible programs. Most importantly, it meant having access to the best possible machines and the most useful information at all times. Hackers spoke openly about changing the world through software, and Stallman learned the instinctual hacker disdain for any obstacle that prevented a hacker from fulfilling this noble cause. Chief among these obstacles were poor software, academic bureaucracy, and selfish behavior.
Stallman also learned the lore, stories of how hackers, when presented with an obstacle, had circumvented it in creative ways. Stallman learned about “lock hacking”, the art of breaking into professors’ offices to “liberate” sequestered terminals. Unlike their pampered Harvard counterparts, MIT faculty members knew better than to treat the AI Lab’s terminal as private property. If a faculty member made the mistake of locking away a terminal for the night, hackers were quick to correct the error. Hackers were equally quick to send a message if the mistake repeated itself. “I was actually shown a cart with a heavy cylinder of metal on it that had been used to break down the door of one professor’s office”,[5] Stallman says.
Such methods, while lacking in subtlety, served a purpose. Although professors and administrators outnumbered hackers two-to-one inside the AI Lab, the hacker ethic prevailed. Indeed, by the time of Stallman’s arrival at the AI Lab, hackers and the AI Lab administration had coevolved into something of a symbiotic relationship. In exchange for fixing the machines and keeping the software up and running, hackers earned the right to work on favorite pet projects. Often, the pet projects revolved around improving the machines and software programs even further. Like teenage hot-rodders, most hackers viewed tinkering with machines as its own form of entertainment.
Nowhere was this tinkering impulse better reflected than in the operating system that powered the lab’s central PDP-6 mini-computer. Dubbed ITS, short for the Incompatible Time Sharing system, the operating system incorporated the hacking ethic into its very design. Hackers had built it as a protest to Project MAC’s original operating system, the Compatible Time Sharing System, CTSS, and named it accordingly. At the time, hackers felt the CTSS design too restrictive, limiting programmers’ power to modify and improve the program’s own internal architecture if needed. According to one legend passed down by hackers, the decision to build ITS had political overtones as well. Unlike CTSS, which had been designed for the IBM 7094, ITS was built specifically for the PDP-6. In letting hackers write the systems themselves, AI Lab administrators guaranteed that only hackers would feel comfortable using the PDP-6. In the feudal world of academic research, the gambit worked. Although the PDP-6 was co-owned in conjunction with other departments, A.I. researchers soon had it to themselves.[6]
ITS boasted features most commercial operating systems wouldn’t offer for years, features such as multitasking, debugging, and full-screen editing capability. Using it and the PDP-6 as a foundation, the Lab had been able to declare independence from Project MAC shortly before Stallman’s arrival.[6]
As an apprentice hacker, Stallman quickly became enamored with ITS. Although forbidding to most newcomers, the program contained many built-in features that provided a lesson in software development to hacker apprentices such as himself.
“ITS had a very elegant internal mechanism for one program to examine another”, says Stallman, recalling the program. “You could examine all sorts of status about another program in a very clean, well-specified way”.
Using this feature, Stallman was able to watch how programs written by hackers processed instructions as they ran. Another favorite feature would allow the monitoring program to freeze the monitored program’s job between instructions. In other operating systems, such a command would have resulted in half-computed gibberish or an automatic systems crash. In ITS, it provided yet another way to monitor the step-by-step performance.
“If you said, `Stop the job,’ it would always be stopped in user mode. It would be stopped between two user-mode instructions, and everything about the job would be consistent for that point”, Stallman says. “If you said, `Resume the job,’ it would continue properly. Not only that, but if you were to change the status of the job and then change it back, everything would be consistent. There was no hidden status anywhere”.
By the end of 1970, hacking at the AI Lab had become a regular part of Stallman’s weekly schedule. From Monday to Thursday, Stallman devoted his waking hours to his Harvard classes. As soon as Friday afternoon arrived, however, he was on the T, heading down to MIT for the weekend. Stallman usually timed his arrival to coincide with the ritual food run. Joining five or six other hackers in their nightly quest for Chinese food, he would jump inside a beat-up car and head across the Harvard Bridge into nearby Boston. For the next two hours, he and his hacker colleagues would discuss everything from ITS to the internal logic of the Chinese language and pictograph system. Following dinner, the group would return to MIT and hack code until dawn.
For the geeky outcast who rarely associated with his high-school peers, it was a heady experience, suddenly hanging out with people who shared the same predilection for computers, science fiction, and Chinese food. “I remember many sunrises seen from a car coming back from Chinatown”, Stallman would recall nostalgically, 15 years after the fact in a speech at the Swedish Royal Technical Institute. “It was actually a very beautiful thing to see a sunrise, ’cause that’s such a calm time of day. It’s a wonderful time of day to get ready to go to bed. It’s so nice to walk home with the light just brightening and the birds starting to chirp; you can get a real feeling of gentle satisfaction, of tranquility about the work that you have done that night”.[7]
The more Stallman hung out with the hackers, the more he adopted the hacker worldview. Already committed to the notion of personal liberty, Stallman began to infuse his actions with a sense of communal responsibility. When others violated the communal code, Stallman was quick to speak out. Within a year of his first visit, Stallman was the one breaking into locked offices, trying to recover the sequestered terminals that belonged to the lab community as a whole. In true hacker fashion, Stallman also sought to make his own personal contribution to the art of lock hacking. One of the most artful door-opening tricks, commonly attributed to Greenblatt, involved bending a stiff wire into a cane and attaching a loop of tape to the long end. Sliding the wire under the door, a hacker could twist and rotate the wire so that the long end touched the door knob. Provided the adhesive on the tape held, a hacker could open the doorknob with a few sharp twists.
4.
See Steven Levy,
Levy devotes about five pages to describing Gosper’s fascination with LIFE, a math-based software game first created by British mathematician John Conway. I heartily recommend this book as a supplement, perhaps even a prerequisite, to this one.
5.
Gerald Sussman, an MIT faculty member and hacker whose work at the AI Lab predates Stallman’s, disputes this memory. According to Sussman, the hackers never broke any doors to retrieve terminals.
6.
I apologize for the whirlwind summary of ITS’ genesis, an operating system many hackers still regard as the epitome of the hacker ethos. For more information on the program’s political significance, see Simson Garfinkel,