If you have ever read anything about the history of UNIX, you may remember that its early development was influenced by an older operating system. MULTICS was developed in the 1960s by MIT and General Electric as a commercial operating system, and had been the system which UNIX writers [Thompson] and [Ritchie] had used. It became a Honeywell product, and the source code for its final commercial version was eventually released to the public. Has it become a dusty relic of interest only to historians? Seemingly not, because a new version has been released. It’s intended for us on the dps8m Honeywell mainframe simulator rather than physical hardware, so perhaps while it’s not such a dusty relic it remains something only for the enthusiast.

We won’t pretend to be experts on the architectures of 1960s mainframe operating systems, but it’s interesting to read for a moment about what it was in MULTICS that caused UNIX to be written. For something described by [Ken Thompson] as “Close to unusable”, with a fresh release in its 52nd year it isn’t doing badly.

We’ve traced the UNIX story in the past, without realising that MULTICS never entirely went away. Shame on us for the omission!

[Via Hacker News]