There's a talk from 1986 by Richard Hamming at Bellcore, about how to do great research, but it also ends up in a short discussion about the conditions there that led to UNIX:
http://www.paulgraham.com/hamming.html
The whole talk is really excellent, and there's this theme in it that the really great things come from some unexpected places, by the compounding of seemingly unrelated character traits, work habits and organization dynamics.
At the end in the Q&A, Hamming gets into a short discussion with the host Alan Chynoweth about the origins of UNIX, evincing from Alan a favorite quote:
"UNIX was never a deliverable!"
expanded:
"Hamming: First let me respond to Alan Chynoweth about computing. I [was in charge of] computing in research and for 10 years I kept telling my management, ``Get that !&@#% machine out of research. We are being forced to run problems all the time. We can't do research because we're too busy operating and running the computing machines.'' Finally the message got through. They were going to move computing out of research to someplace else. I was persona non grata to say the least and I was surprised that people didn't kick my shins because everybody was having their toy taken away from them. I went in to Ed David's office and said, ``Look Ed, you've got to give your researchers a machine. If you give them a great big machine, we'll be back in the same trouble we were before, so busy keeping it going we can't think. Give them the smallest machine you can because they are very able people. They will learn how to do things on a small machine instead of mass computing.'' As far as I'm concerned, that's how UNIX arose. We gave them a moderately small machine and they decided to make it do great things. They had to come up with a system to do it on. It is called UNIX!
A. G. Chynoweth: I just have to pick up on that one. In our present environment, Dick, while we wrestle with some of the red tape attributed to, or required by, the regulators, there is one quote that one exasperated AVP came up with and I've used it over and over again. He growled that, ``UNIX was never a deliverable!''"