Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!gem.mps.ohio-state.edu!ginosko!uunet!cme!libes
From: libes@cme.nbs.gov (Don Libes)
Newsgroups: comp.os.xinu
Subject: Re: xinu simulator (runs under unix?)
Keywords: xinu unix simulator
Message-ID: <1536@muffin.cme.nbs.gov>
Date: 25 Aug 89 21:39:24 GMT
References: <9199@cbnews.ATT.COM>
Reply-To: libes@cme.nbs.gov (Don Libes)
Organization: National Institute of Standards and Technology
Lines: 25

In article <9199@cbnews.ATT.COM> mss@cbnews.ATT.COM (Mark S. Shaw) writes:
>I have heard that there is a xinu simulator available which runs as a single
>UNIX process. I would appreciate information on how it can be obtained.

This appeared in the July/August 1987 ;login: as "Multiple Programs in
One UNIX Process".  It is available by anonymous ftp from
durer.cme.nist.gov as xinu.shar.Z

Xinu/UNIX may not be everything you want.  It cheats as much as
possible.  For example, when programming with it, you use the regular
UNIX device drivers, cc, ld, C startup routines, etc.  Bear in mind
that it wasn't done as an experiment or to show anything - rather, it
was done because it provided us with threads (i.e. lightweight
processes).  Nonetheless, the system demonstrates the elegance of Xinu
and what it is all about.

Doug Comer told me that some of his students also wrote one which they
called "Concurrent C".  It uses a second process to handle I/O.  This
avoids the restriction that calling a UNIX device driver blocks the
entire set of Xinu processes.  (Our application wasn't concerned with
this.)

The paper I referred to earlier goes into more detail on all of this.

Don Libes          libes@cme.nist.gov      ...!uunet!cme-durer!libes