Subject: [FreeVMS] Re: Development
From: David Elins (david@elins.net)
Date: Sun Dec 01 2002 - 19:31:02 CET
I think VMS, at least in its original implementation had an interrupt-based
kernel.
That is, rather than being based on a master event-loop, after the initial
boot, all process scheduling, resource allocation,
and all the other junk an operating system cares about was based on
handling interrupts.
As I recall there were 64 levels of interrupts (and I am sure someone will
correct me if i am wrong!) with higher numbers taking precedence (i.e. a
higher-level interrupt could preempt a lower-level interrupt service
routine). The highest 32 levels were reserved for hardware devices and
there was a fairly high-level timer interrupt to (among other things)
ensure that no process or thread hogged the processor.
I agree with Chris - I think it would be fun to develop a new (VMS-like) OS
based on new concepts (concepts that
mirror the way the world works!).
David Elins
At 03:33 PM 11/30/2002 -0800, you wrote:
>I think the first step is some contingent plans to divorce the kernel from
>it's linux base. Although it gives an excellent framework for initial
>development and surely some algorithms and routines would be quite
>ridiculous to try to re-engineer or re-write but as in the case of lainos,
>we wish to in fact make an independent system that duplicate vms, not
>linux.
>
>On Fri, 29 Nov 2002 roart@nvg.ntnu.no wrote:
>
> >
> > On Thu, Nov 28, 2002 at 10:45:15AM -0800, Chris McKenzie wrote:
> > > Count me in to. I'm working on porting NetBSD and a few emulators so I
> > > have some experience in the design. I have read some books on VMS and
> > > have used it in a very limited sense
> >
> > What do you want to do to start with?
> >
> > Regards,
> > Roar Thronæs
> >
> >
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> >
> >
> >
>
>Sincerely,
> Christopher J. McKenzie
>
> cjm@ucdavis.edu
> mckenzie@cs.ucdavis.edu
> H: +1 818.9917724
> C: +1 818.4293772
> 1815 Mesa Ridge Ave
> Westlake Village, CA 91362
>
>
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