M.I.T.'s Information Services and Technology organization has released the source code of MULTICS, a decades-old OS and important forebear of modern day operating systems.

Although there are no systems in operation today that could run MULTICS, the code release may serve as a fascinating research tool for computer scientists and academia.

MULTICS (or Multiplexed Information and Computing Service), began its incarnation in 1964 as a joint project between M.I.T., General Electric and Bell Labs. The operating system was developed for the GE-645 mainframe, a 36-bit general purpose time-share system built for continuous operation. The idea was to provide a computing utility analogous to electricity and telephone services.

It was one of the first operating systems to introduce concepts such as a hierarchical file system and dynamic linking. It was also the first to use the modern standard of per-process stacks in the kernal, with a separate stack for each security ring. The last running Multics system was shut down on October 31, 2000.

Some of the people who originally worked on the project, including Dennis Ritchie, Doug McIlroy and J.F. Ossana went on to create the Unics operating system — later renamed Unix. Evidence of Unix's heritage can still be found in its naming of commands. The story goes that the "U" in Unix stands for Uniplexed, a play on "Multiplexed" in the MULTICS namesake.

The final MULTICS release, MR 12.5 of November 1992, can be downloaded here. ®

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