Re: [9fans] Interesting in trying out Plan 9

[dmr@plan9.bell-labs.com]

 >> Unless "minix" refers to more than one OS,
 >> Tanenbaum's work was, again, I believe, clean-room.

 > I'm not entirely sure whether that's true, where clean-room
 > means "without tainting by knowledge of the original".

 > When describing
 > the history of MINIX in his Operating Systems, he notes that
 > V6 was used in courses, but V7 could not be. ...

 > Which happens to avoid mentioning whether Tanenbaum was familiar
 > with the V6 sources. The impression I've generally had was that
 > MINIX was deliberately different, rather than by mere accident
 > through unfamiliarity with V6 internals.

The issue of tainting didn't come up from our point of view
with MINIX, nor in several other situations (e.g. Idris, or
the Mark Williams Coherent system).  It was clearly enough an
independent implementation of described mechanisms.
Nevertheless Tanenbaum and Plauger were both cautious
in providing some visible distance in their specifications.
But of course they also had reasons of their own
for specifying interfaces in a way more congenial to
their own purposes.

In the later BSDi/UCB case, USL convinced themselves
that BSDi was not only commercial (true)
but also that the 'tainting' was more a matter of 10-year
saturation and history of licensed release from UCB.  This
implied to USL that the emancipated BSD and BSDi code
must have been copied.

There's some moral argument for this case, but the other
facts (little evidence of direct copying, questionable
copyrights, existing public standards) failed to convince
the judge.

	D.