All, My IEEE Spectrum article finally got published and you can read it on-line here: http://spectrum.ieee.org/computing/software/the-strange-birth-and-long-life… I've had a few e-mails about it. This one has a few more snippets about early Unix history (from Rey Bonachea): It was with great pleasure and a bit of nostalgia that I read your IEEE article below. Thank you very much for writing it. One aspect that did not get mention, and that perhaps you may or may not be aware of, was the pseudo real time applications of Unix. In 1972 I joined Bell Labs in Holmdel NJ working on a project by the name of Switching Control Center System. At the beginning I was just a brand new member of the technical staff working on circuit design for interfaces to the PDP11/20. This project was meant to centralize the data streams from the maintenance channel of switching machine. Then, in a multi-user environment , would analyze the incoming data streams and raise alarms as appropriate. It also provided a whole suite of analysis tools to allow switch maintenance personnel to trouble shoot the electronic switches. Because the switches could not buffer messages or be slowed by flow control, the Unix system had to catch messages in real time and put it away on disk for later analysis. Due to the near real time requirements, a number of features were added to Unix such as semaphores. The Unix based Switching Control Center System (SCCS) software was trialed in New Brunswick NJ in 1973 and later that year was released as the first commercial application of the Unix OS. I learned to program on that PDP 11/20 computer running Unix and eventually wrote many applications for the SCCS, initially in assembly language and then in C as we were also the first project to use C commercially. Cheers, Warren