Messages in this thread | | | From | Marty Fouts <> | Subject | RE: Topic for discussion: OS Design | Date | Sun, 22 Oct 2000 22:58:46 -0700 |
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FWIW, 'message passing' is the wrong answer to the question 'how do I separate the components of a kernel into distinct modules for <mumble>' but that's because it's tied to the Accent ancestry of the Mach style "microkernel".
One of the few things we did get right in Brevix was the idea of an interface transition that used the memory management architecture of PA-RISC effectively to give the modularity and production without the overhead of message passing. If you want someone to add components to hardware to support that, get them to set up a system that effectively separates memory addressability from memory accessability, as PA-RISC did. (Oh wait, we did that. If Intel didn't throw it away, Itanium *will* have such an architecture.)
Crossing memory protection domains does not need to be slow. It's not in PA-RISC, although it is in the VAX-ish memory architecture of systems like x86. It doesn't have to be in IA-64, if one is willing to abandon 'legacy.'
-----Original Message----- From: Dwayne C . Litzenberger [mailto:dlitz@dlitz.net] Sent: Sunday, October 22, 2000 8:57 PM To: Erno Kuusela Cc: linux-kernel@vger.kernel.org Subject: Re: Topic for discussion: OS Design
[snip] > crossing memory protection domains is slow, there's no way around > it (except better hardware).
So what we really need to do is get some custom "RAM blitter" into our hardware to do the memory copies needed for fast context switching and message passing.
Too bad nobody on this list works at an electronics design company... ;-P
-- Dwayne C. Litzenberger - dlitz@dlitz.net
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