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Best obscure mainframe OS?


25k Member
Jan 11, 2007
Pacific Northwest, USA
Ever hear of Zodiac? CDC had about $180M in revenue in the early 70s with that one--and I was involved with it until its termination around 1975. For a time, the same OS core was rechristened TOOS and used at UBS Switzerland. The basis of Zodiac was TCM/RA1--a time-critical monitor developed in Special Systems in the late 60s. Zodiac was very different from anything CDC offered at the time. Shame there's almost nothing on the web about it.

I was fascinated at the time with 7600 SCOPE 2--very unlike its 6000-series relatives. Internals were very different, because the CP-to-PP relationship is different (e.g. a PP couldn't modify CM outside of its hard-wired buffer area). The SCOPE 2 people for a time, were in an adjoining cube cluster at SVLOPS and I wish I'd kept my documentation that I collected.

NOS/BE was essentially SCOPE 3.4 re-named and perhaps tarted-up a bit. Lots of renaming going on at the time; e.g. 6RM became CRM, which completely obscured a very obvious difference between it and 7000 SCOPE 7RM, which preceded it.

KRONOS/NOS was based on MACE an OS originally bootlegged by Dave Callender and Greg Mansfield on the QA floor at ARHOPS. (MACE = Mansfield's Answer to Customer Engineering). Code from that was appropriated and modified by several organizations, amongst which was Purdue U.
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