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SubjectRe: [PATCH] scheduler patch, faster still
On Tue, Sep 29, 1998 at 07:57:43AM -0700, D.A. Harris wrote:
> Well, it wouldn't be waste if you are implementing a voice mail system for
> say 400 users. If the RT stuff was stable and reliable you could challenge
> Qunix in that market.

RTlinux already does that. The reason why the RT stuff in RTLinux is not
in the main kernel is that it is exceptionally difficult to make
a time sharing general purpose kernel also do real-time.
Scheduling may help, but there are serious problems with
1. interrupt processing
2. memory management
3. the numerous shared data structures guarded by sleep
...

Linux is designed to be non-preemptive in kernel mode. That's a common
and smart design, but it makes "real-time" impossible. There is no
point in putting racing tires on a Jeep.



---------------------------------
Victor Yodaiken
Department of Computer Science
New Mexico Institute of Mining and Technology
Socorro NM 87801
Homepage http://www.cs.nmt.edu/~yodaiken
PowerPC Linux page http://linuxppc.cs.nmt.edu
Real-Time Page http://rtlinux.org

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