VM/370 Security (and performance)

[Karl Danz]

> I'm grateful to the colleague who finally gave the most reasonable
> explanation of VM to me:  IBM couldn't figure out how to build a multi-user
> shared system, so they found something that would let single-user systems
> battle it out in a machine.

The way I heard it, VM came into being to fill a need within IBM:
they wanted to let lots of people do operationg systems development
work without handing over a megabuck machine to every one of them.
CMS was to be nothing more than a file system, an editor, and a few
other tools with which to do this work.

That VM was pried from IBM by customers who reasoned that there MUST
be more to this world than MVS, and that VM has flourished, speaks
well of it.  Most of the problems which have been identified in this
discussion arise from the difference between VM's designed use and
its real (meaing current day) use.  It's still the only way to go for
developing and testing 370 architecture operating systems.

I can certainly think of one other major operating system which is now
being used for things the original authors would never have dreamed of!

					Karl Danz
					Cygnet Systems
					...!hplabs!cygnet!karl