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From: jfh@rpp386.cactus.org (John F. Haugh II)
Newsgroups: comp.unix.wizards
Subject: Re: What new system calls do you want in BSD?
Message-ID: <17899@rpp386.cactus.org>
Date: 10 Feb 90 01:45:06 GMT
References: <11102@encore.Encore.COM> <7904@pt.cs.cmu.edu>
Reply-To: jfh@rpp386.cactus.org (John F. Haugh II)
Distribution: usa
Organization: Lone Star Cafe and BBS Service
Lines: 21

In article <7904@pt.cs.cmu.edu> dstewart@fas.ri.cmu.edu (David B Stewart) writes:
>Another feature that would be useful as a BSD system call is to
>lock down one or more pages in physical memory, and allow other
>processors on a common backplane to mmap it.  Of course, this assumes
>appropriate hardware architecture.

It is actually possible to mmap() files over the wire - including
such transport mechanisms as SL/IP or Morse Code over a spark gap
rig.

>As an example, suppose one CPU is running BSD UNIX, while all others have
>some kind of Real-Time OS (our current situation, except we have SunOS). 
>It is possible for the UNIX machine to mmap part of the other CPUs
>memory; but the reverse is not possible.

Anything is possible.  Just sit down and dream up some way to make it
work.  There is nothing special about "real time", provided the "real
time" constraints are met.
-- 
John F. Haugh II                             UUCP: ...!cs.utexas.edu!rpp386!jfh
Ma Bell: (512) 832-8832                           Domain: jfh@rpp386.cactus.org