Re: Oracle ventures into the O/S market.....?

Kevin Closson wrote,on my timestamp of 19/04/2006 2:47 AM:

>
> Oh boy. Something tells me you haven't had your hands in the
> Informix DSA code as much as I have. The threads scheduler in
> that database server was anything BUT "simple time-sharing
> round-robin threads". It was a brilliant database-smart scheduler
> and as long as it ran on a good OS, you very seldon saw more than
> 5% of your processor cycles lost to kernel mode...and that
> even at extremely high IO rates.

I must admit my knowledge of Informix stopped in 86: didn't bother after that.

Still, if you spend the time scheduling in kernel mode or database/user mode, it doesn't matter one tick: you are still scheduling, the only change is the name.

Yeah, I know: context switches and all that. You still have to have them unless you completely replace the OS IO layer, in which case your system stops being a general purpose computing facility and becomes a database-only machine.

Those were a short-lived fad: no one can afford such specialized systems anymore and most implementations just died out. Sybase was an example of one that survived by converting to all-software instead of needing a dedicated computer to run. But it's still the same old problem: if you put everything in user mode, (or "db mode", semantics here) then it stops being a general purpose OS.

What is needed is efficient ring architectures, but those need another two or three years to flush out properly. And they'll be used first for simulating VM-like environments with multiple concurrent OSs in the same multi-core CPU.

-- 
Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision_at_iinet.net.au
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