[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Edlug Archive Mar 2004 ]

Re: [edlug] Is Open Source a Viable Business Alternative?

>>>>> Greg Lewin wrote (on Thu, 11 Mar 2004 at 18:39):

    > Peter G. Hancock wrote:
    >> ... They invented VM.

    > What VM - do you mean Virtual Memory? I thought that was invented in
    > the UK, at Manchester.

I mean the thing that virtualises the machine/architecture (370?) it
runs on so it could run all sorts of operating systems underneath
itself, and even itself... and so on.  You're probably right virtual
memory was down to us Brits.

This was apparently incredibly commercially valuable, particularly for
customers who wanted to run systems in "dry run" alongside their
existing systems before committing to an upgrade.  And various other
reasons. (VM was done as a midnight project by a scientific programming
group in IBM, I'm unreliably told.) 

The "idiom" of virtualisation pervaded lots of other operating systems
at the time. Various ICL os's had a cool way of presenting programs
with virtual devices -- tape punches, card readers, mag tapes, etc
etc.  I think Tony Hoare, who was at General Electric (Eliot?) in the
60's had a big influence on promulgating the idea.  One of his
earliest papers was on a paging system, and it's a theme that recurs
in his writings.

Myself, I think that virtual machines are bound to become more and
more important (again), as machine capacity increases, and the
environments (M$, etc) that pieces of software want to run in become
increasingly insane.


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