From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Eckhardt <davide+p9@cs.cmu.edu>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] [OT] linux origins, why not?
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Date: Thu, 30 Mar 2006 13:14:57 -0500
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> i don't see how mach is an improvement over linux.  especially
> early linux.  mach kernels were three times the size of linux
> kernels of the day and didn't do anything useful by themselves.

What the AT&T lawsuit blocked distribution of was Mach 2.5, which
was BSD Unix with parts of the kernel replaced.  One unified source
tree ran on several architectures (VAX, 68k, MIPS, x86; later 88k,
Sparc).  Commercial multiprocessor Unix machines were sold running
that code base (the Encore Multimax, and I *think* the Sequent
Symmetry).

As for utility, Mach on VAX and 68k Sun and DEC PMAX and PC hardware
was the computing environment for hundreds of people at a time at CMU
for a good chunk of a decade.  Multiprocessor desktop workstations
(4-way 88k "Luna" boxes made by Omron) were not uncommon in 1992.
By no means was it perfect, and it was never really good at the
distributed-computing thing, but I think it would have provided *very*
stiff competition for Linux if it hadn't been embargoed.

Dave Eckhardt