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From: steve@mimsy.UUCP (Steve D. Miller)
Newsgroups: comp.unix.wizards,comp.emacs,comp.os.minix
Subject: Re: CMU's Mach in public domain?
Message-ID: <5869@mimsy.UUCP>
Date: Wed, 18-Mar-87 11:23:23 EST
Article-I.D.: mimsy.5869
Posted: Wed Mar 18 11:23:23 1987
Date-Received: Fri, 20-Mar-87 01:51:05 EST
References: <155@lmi-angel.UUCP>
Reply-To: steve@mimsy.UUCP (Steve D. Miller)
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 27
Xref: mnetor comp.unix.wizards:1515 comp.emacs:605 comp.os.minix:429

Well...  I haven't heard anything specific, but this is what I know from
looking at the Mach sources we have:  the Mach kernel proper (nifty IPC,
nice virtual memory, tasks/threads, and that's it) is apparently written
from scratch, and, if so, is something that the Mach people *could* put in
the public domain if they so choose.  However, the comment about Unix
compatibility is a little misleading.  Sure, Mach is 4.3BSD binary
compatible, but it's not like they rewrote all of 4.3 to make it so.  They
basically sawed off the bottom layers of the Berkeley kernel (i.e., anything
that touches the virtual memory stuff is changed), but left the upper layers
intact.  And *that* they can't just give away.  We had to show source
licenses for SunOS and 4.3BSD before we could get a copy of the Mach kernel
plus its Unix-lookalike wrappers for both Suns and vaxen.

As an interesting aside, the Sun version of Mach is mostly 4.3-based; for
example, the Mach group didn't put NFS back in (they have their own), and I
don't think they put pixrects back in (I do know that the last time I heard,
SunView didn't work and they were telling people to use X).  They did grab a
lot of device drivers, though, and probably some other stuff.

	-Steve



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