Plan 9 license

[Matthew C. Weigel]

On Mon, 21 Aug 2000, David Johnson wrote:

> > I'm not certain I agree with that, myself.  Its requirement that
> > licensees choose between licensing Plan 9 and being able to protect
> > their intellectual property is particularly onerous.  The right of Bell
> > Labs to demand private source is also unacceptable.
> 
> I don't see anything in the OSD forbidding the demand of private
> derivations. This clause is certainly pretty poor, but it doesn't go
> against the *letter* of the OSD.

Read what I said again.  I'm saying it should be in the OSD, because the
clauses are "particularly onerous" and "unacceptable." I would argue the OSD
was not, is not, and never will be an airtight document whose letter you can
follow, but whose spirit you can ignore; the letter of the definition was
largely thrown together, in an attempt to encapsulate the spirit.  Others
can say, "here, approximately, is what Open Source is," but the OSI and the
open source community should focus on the spirit, and when inconsistencies
arise, correct the letter, and not say "oh, we forgot to mention that
freedom, so we'll just roll over and ignore that it was ever important to
us." Yes, that means people submitting new licenses may be caught by
surprise; but OSI Certification should not be an assembly line production,
but a discussion (a discussion including the license's authors, so that
questions and explanations of intent, that might clarify a clause or get a
clause changed, can happen).

> To quote from the page in question, "More precisely, it refers to four
> kinds of freedom, for the users of the software... A program is free
> software if users have all of these freedoms. " This seems to sum it up
> for me. The rest is just commentary.

Yes, four *kinds* of freedom -- to be explained further in the document;
think of it as an explanation and statement of intent.  The document is not
the four bullet points, and the clarifications and explanations included
discuss those four freedoms as RMS sees them.  In order to have those four
kinds of freedom, there are preconditions, clarifications, and explanations
involved as well -- as discussed later in the document.

> Later on, he does make some clarifications. One of them (I found two)
> is: "but what they can and must do is refuse to impose them [export
> control regulations] as conditions of use of the program". This may
> apply to the Plan 9 license.

I think it's pretty clear it does ("can and must").  It would also be a part
of freedom #2, the freedom to redistribute copies so you can help your
neighbor.  I think it's also pretty clear you were not reading very closely;

	In order for these freedoms to be real, they must be irrevocable as
	long as you do nothing wrong; if the developer of the software has
	the power to revoke the license, even though you have not given
	cause, the software is not free.

This goes back to the IP suit clause in the Plan 9 license, and is also
clearly a requirement for being free software -- you must have the four
freedoms, and the four freedoms must be real.

>                              But whether this clarification is part of
> the Free Software definition is, in my mind, debatable, as it still
> meets the four necessary and sufficient freedoms stated at the top of
> the page.

No.  If you want to say "necessary and sufficient," then look at it like a
theorem, and you'll see again what I'm saying.  Each of those conditions
has, on its own, necessary and sufficient conditions, all of which must be
satisfied for the condition -- the freedom listed in the bullet point -- to
be present.  You can't simply wave your hand, say "you have the freedom to
redistribute copies to help your neighbor, except you have to restrict this
freedom according to US export law," and have the statement "you have the
freedom to redistribute copies to help your neighbor" unconditionally.

The only one I can see that is open to interpretation is this clause:

	You should also have the freedom to make modifications and use them
	privately in your own work or play, without even mentioning that
	they exist.

The use of "should" rather than "must" causes it to appear that this is
optional, but strongly encouraged.  This freedom would fall under 

	o The freedom to study how the program works, and adapt it to your
	needs....

However, if you have "the freedom to study how the program works," should
that not imply that your licensed ability to study how the program works --
which includes modifications as a matter of experimentation -- must not be
limited by notification to third parties?  And if no third parties (the
licensor included) need be notified for private copies, how can private
modifications be required to be submitted to a third party?

I'll say it one last time, and then I'll try not argue this point with you
again.  Without reading the entire document, you are not grasping what the
four kinds of freedom described are and require; claiming to have one of the
freedoms, while not providing the fullness of that freedom, does not achieve
free software status.

 Matthew Weigel
 Programmer/Student
 weigel+ at pitt.edu