On Wed, 13 May 1998 14:52:14 -0400 
 rbraun@cstone.net (Rolf Braun) wrote:

 > And what about the following text controls _how_ the source is distributed?
 > 
 > /*
 >  * Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
 >  * Regents of the University of California.
 >  * All rights reserved.
 >  *
 >  * Redistribution and use in source and binary forms, with or without
 >  * modification, are permitted provided that the following conditions
 >  * are met:

 >  * 1. Redistributions of source code must retain the above copyright
 >  *    notice, this list of conditions and the following disclaimer.

Read this clause very carefully and think about what it means.

 > >(4) VM system - we have UVM.  Chuck Cranor did a new VM system to
 > >    address the problems in the Mach VM system, rather than continuing
 > >    to tweak the Mach VM system... in many ways, this was the Right Thing,
 > >    and very typical of the NetBSD way of doing things .. "If it sucks,
 > >    start from scratch and do it right!"
 > 
 > "If it ain't broke, don't break it."
 > 
 > Mach VM may have had some problems, but it worked reliably. I can't say the
 > same for UVM so far, especially not on mac68k.

Mach VM is definitely broken, in several ways.  UVM has been much more
reliable on my primary platform, the Alpha.  It still has some bugs to
shake out, but overall, it is a much better VM system than Mach VM.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
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