Conversation so far:
What did Richard Stallman do at Harvard?
As a first-year student at Harvard University in fall 1970, Richard Stallman was known for his strong performance in Math 55.
What did Richard Stallman do at MIT?
Richard Stallman pursued a doctorate in physics for one year at MIT, but left that program to focus on his programming at the MIT AI Laboratory.
What else did you find interesting with Richard Stallman at Harvard and MIT besides pursuing physics and his strong performance in Math 55?
While working as a research assistant at MIT under Gerry Sussman, Richard Stallman published a paper in 1977 on an AI truth maintenance system, called dependency-directed backtracking.
Was Richard Stallman well liked at MIT?

Question: How long was the MIT tenure?
Self-contained rewrite: How long was Richard Stallman's MIT tenure?