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From: "Brian Catlin" <briancatlin@mindspring.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada OS Kernel features
Date: Wed, 5 Sep 2001 23:56:47 -0700
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"Tarjei T. Jensen" <tarjei.jensen@kvaerner.com> wrote in message
news:9n762l$7ah4@news.kvaerner.com...
>
> Brian Catlin wrote
> >Well, I wouldn't hold Mach up as the end-all or be-all of operating system
> >kernels; its performance is nothing to brag about.  It certainly has many
> >interesting concepts, but its overhead is too high for my taste (I haven't
> >looked at it in several years, so it may have been cleaned up; I'll have to
> go
> >check it out again).
>
> As I recall Mach is supposed to represent a snapshot of microkernel
> technology at a relative early stage. I believe that at least IBM has
> advanced the state of the art considerably since mach was released.

Yes, I just looked at RT-Mach (Real-Time Mach), and it is quite impressive - as
far as microkernels go.  The big problem with microkernels is that you have to
use RPC to communicate between services, which is much more expensive than a
simple CALL in a monolithic kernel.

 -Brian