[geeks] Re: [rescue] Re: kernel scalability....

[Ken Hansen]

Dave,

I suspect that the CPU is *so fast* that if the mainframe were to run a
single thread, the relatively slow I/O would really bog down the process (as
measured in *clock time*, not CPU time).

In my (casual) experience, mainframes have an incredible ability to absorb
more tasks without effecting clock time for a given task too much, much like
a bus - it doesn't take longer to move 50 people from here to there than if
there were only one person in the bus...

As i understand it, the *nix kernel does one thing at a time, and task
switches based on time slices - in such an implementation of a "classic"
*nix kernel on a mainframe, you would spend most of your time waiting for
I/O devices. But this is a *real* simplification, but I think it holds true
as details are added/model refined to closer map the actual tasks
involved...

Ken

----- Original Message -----
From: <dave at cca.org>
To: <geeks at sunhelp.org>
Sent: Sunday, September 09, 2001 9:53 PM
Subject: [geeks] Re: [rescue] Re: kernel scalability....


> However - why does running multiple unix instances under VM help?
>
> Is this a context-switch-to-hide-latency type effect, like barel
> processors use?



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