The MIT Artificial Intelligence Laboratory (AI Lab) was the research institution where stallman worked as a programmer from 1971 through the early 1980s. It is the formative environment for Stallman's understanding of software as a shared resource and for the hacker-ethic-mit that underlies the free-software-definition.
The AI Lab during the mit-ai-lab-hacker-culture-1971-1984 era operated on a culture of open access and free sharing of software. Programmers were expected to share their improvements, fix bugs they encountered, and leave systems open for others to use and modify. This was not a formal policy but a deeply held ethic that stallman experienced as natural and correct.
gerald-sussman and guy-steele were among the prominent researchers at the AI Lab during this period. Sussman was Stallman's mentor. The hackers-levy book by steven-levy documents this culture in detail.
The culture began to erode in the late 1970s and early 1980s as commercial software companies recruited AI Lab programmers and began treating software as proprietary. Stallman's response to this erosion — including incidents such as the Xerox printer driver episode — directly motivated the announcement-of-gnu-project and the founding-of-fsf.
The AI Lab was later merged with the Laboratory for Computer Science to form MIT CSAIL (Computer Science and Artificial Intelligence Laboratory). The original AI Lab's culture is the historical baseline against which Stallman measures the software industry and finds it wanting, and it is the experiential foundation for the four-freedoms he articulated in the free-software-definition.