Unix was a very small, understandable OS, so people could change it at their will. It would run itself—you could type "go" and in a few minutes it would recompile itself. You had total control over the whole system. So it was very beneficial to a lot of people, especially at universities, because it was very hard to teach computing from an IBM end-user point of view. Unix was small, and you could go through it line by line and understand exactly how it worked. That was the origin of the so-called Unix culture.

"Unix and Beyond: An Interview with Ken Thompson," 1999