From: Russell Miller <rmiller@duskglow.com>
To: Doug McNaught <doug@mcnaught.org>
Subject: Re: is killing zombies possible w/o a reboot?
Date: Wed, 3 Nov 2004 20:45:20 -0500
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On Wednesday 03 November 2004 19:38, Doug McNaught wrote:
> Russell Miller <rmiller@duskglow.com> writes:
> > This brings up another question I've had since reading the documentation
> > on later pentium-class chips:
> >
> > why are only rings 0 and 3 used in linux?
>
> Because the "traditional" Unix privilege model only has two levels,
> and Linux runs on many architectures, most of which have only two
> privilege levels (the 68000 called them "user" and "supervisor").
> Special-casing x86 is possible but probably wouldn't be worth it.
>
Wouldn't it help with device driver problems?  Couldn't ring 1 be used to make 
sure an errant driver doesn't drop the kernel, at least on x86 machines?

I remember the 68000 architecture.  Quite nice (but I was 10 when I studied 
it, so..).

--Russell

> -Doug

-- 

Russell Miller - rmiller@duskglow.com - Le Mars, IA
Duskglow Consulting - Helping companies just like you to succeed for ~ 10 yrs.
http://www.duskglow.com - 712-546-5886
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