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From: anand@amax.npac.syr.edu (Anand Rangachari)
Newsgroups: comp.os.misc
Subject: Re: Mach (was Re: Re^2: Unix bigotry)
Message-ID: <1170@cmx.npac.syr.edu>
Date: 1 Mar 89 17:39:28 GMT
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Reply-To: anand@amax.npac.syr.edu (Anand Rangachari)
Organization: Northeast Parallel Architectures Center
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In article <3471@sugar.uu.net> karl@sugar.uu.net (Karl Lehenbauer) writes:

>because I've only read about it.)  For example, Mach supports the highly
>disparate virtual memory mechanisms of the IBM PC/RT and the Vax.
>A benefit of the Mach VM model: passing big messages to other tasks is
>accomplished by memory mapping rather than copying when possible.  Mach makes
>heavy use of copy-on-write to avoid unnecessary copying, a la BSD's vfork and
>System V fork (System V is superior to BSD is this respect, gasp).

  It is interesting that you bring this up. I attended a talk by Richard
Rashid (designer of Mach) a few days ago when he discussed this point. His
team has been so successfull in getting Mach to run on a number of machines
by essentially not using most of the memory management facilities. In fact,
it seems that programs run faster under Mach than SunOS on the Sun 3 even
though Mach does not make full use of the facilities provided by the Sun
MMU.

                                                      R. Anand

Internet: anand@amax.npac.syr.edu
Bitnet:   ranand@sunrise
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