SAS Systems

[William S. Frantz]

> Can you point me to any on-line reference material on these systems?

No.  I will think a bit about recomended books.  

OS/360/MVT did offer a form of protection domain.  (Remember here we are
talking really old technology, before IBM "invented" virtual memory.)
OS ran on a machine without mapping (or page faults), so it was a
real memory system.  It had 16 protection keys which it used to
protect "jobs" (kind of like users) from each other.  This allowed
15 jobs to run (with the 16th key used by the system).  Each "job"
could have multiple "tasks" (like threads in that they shared the
protection domain).

OS/SVS was like OS/370/MVT except that is supported virtual memory.
It had the same protection scheme.  It was a transistional product
on the path to OS/MVS, the direct ancestor of IBM's current main-
frame offering.  MVS can support more than 16 jobs because it has
multiple address spaces.

If you go to the IBM manuals which describe these systems, probably
the best place to start is with the ones called, "Concepts and
Facilities".

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Bill Frantz                   Periwinkle  --  Computer Consulting
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