[SunRescue] any 3B2 users out there?

[Greg A. Woods]

[ On Wednesday, March 21, 2001 at 22:43:58 (EST), dave at cca.org wrote: ]
> Subject: Re: [SunRescue] any 3B2 users out there?
>
> I remember talking about copy-on-write when we were running 4.3BSD on
> an 11/750 at school. Are you sure it wasn't in there?

I'm not sure.   4.4BSD does include copy-on-write for certain (i.e. in
the CSRG release with the Mach-based VM), and indeed vfork() is
implemented that way in 4.4BSD (but surprisingly not in NetBSD which
reverted to the original vfork() implementation for performance reasons
-- I guess if you're going to explicitly use vfork() in some programs
then you may as well benefit from it).

FYI, Vahalia says in "UNIX Internals" that at lest on the 3B2 less than
1/4 of the pages have to remain unmodified in the child process before
it becomes faster to just copy all pages in advance.

Hmmm... also Vahalia hints that native 4.3BSD does not already have
copy-on-write because he says with the addition of Mach VM it gains that
feature.

> Which touches on a subject I can never get a decent answer on: where
> can I get a free copy of Mach with some sort of unix environment on
> it for a sparc? Old versions are fine.

That's a good question.  Google finds threads in various lists hinting
that there was a CMU port of Mach 2.5 to sparc, but that it's probably
encumbered.  Original CMU Mach 3.0 requires a SunOS/3 source license.

The Mach project at CMU has been shut down, but there's Mach 4 at Utah.

Your best bet is the GNU Hurd -- aka the GNU Mach kernel.  It's not on
sparc yet though as far as I can see.

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods at acm.org>      <robohack!woods>
Planix, Inc. <woods at planix.com>; Secrets of the Weird <woods at weird.com>