itsy bitsy Unix

Well moving back on-topic a little.... I would have thought that there were a number of timesharing operating systems written for the PDP-11 above and beyond those written by DEC. The reason being that -11s were relatively cheap and the architecture isn't too bad compared with some other architectures popular at the same time (ooh, I can feel the flames coming from miles away :-). Now I wouldn't want to write an operating system in assembler, but if you had to, an -11 (or even better a VAX) wouldn't be the worst choice. I can think of two "well known" operating systems written for the -11. These are xinu (http://www.cs.purdue.edu/research/xinu.html) and solo (http://web.syr.edu/~pbhansen/html/biography.html). xinu is written in c and solo in Concurrent Pascal. I remember reading Per Brinch Hansen's "The Architecture of Concurrent Programs", which includes the complete program text of the Solo operating system and suddenly all the concepts of operating system design I had were crystalized into knowledge. Another book on my list of "need to finds".... Another (even more interesting) operating system is Hydra written for the CMU* "Beowulf" of PDP-11s. See http://research.microsoft.com/users/GBell/CGB%20Files/ Cmmp%20CMU%20Multiminiprocessor%20Computer%207108%20c.pdf Huw Davies | e-mail: Huw.Davies at kerberos.davies.net.au Melbourne | "If soccer was meant to be played in the Australia | air, the sky would be painted green"