Free as in Freedom. Richard Stallman’s Crusade for Free Software

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.

When Stallman tried the trick, he found it good but wanting in a few places. Getting the tape to stick wasn’t always easy, and twisting the wire in a way that turned the doorknob was similarly difficult. Stallman remembered that the hallway ceiling possessed tiles that could be slid away. Some hackers, in fact, had used the false ceiling as a way to get around locked doors, an approach that generally covered the perpetrator in fiberglass but got the job done.

Stallman considered an alternative approach. What if, instead of slipping a wire under the door, a hacker slid away one of the panels and stood over the door jamb?