Open Source License Question
kdombrowski at gmail.com
Fri Oct 29 06:03:11 CEST 2004
Hi, I was just browsing the group as a newbie to python, and I would
hate to be thought (or be baited by) a FOSS licensing troll with my
first post, so I apologize if these issues have been gone over already;
in fact several people have said that they have, but I am compelled to
reply to this thread:
Peter Hansen wrote:
> Dan Perl wrote:
>> Michael, I have one comment in-line (see below), but other than that I
>> can only say that I chose GPL for my own project. It may discourage
>> use of my code for commercial purposes
I can only assume you're referring to the restriction that authors of
non-free software can't link to your libraries
With your code under the GPL, anybody can use your code for commercial
purposes, or any other purposes. Anybody can sell it, anybody can link
to it and sell the derivative work, with the provision that in that case
they use the GPL for that derivitave work
> This seems like an appropriate post to which to attach a reference
> to a nice article contrasting the GPL and the Mozilla Public License
> (MPL): http://croftsoft.com/library/tutorials/gplmpl/
> Summary of that essay, in the words of its author:
This is a very misleading article to point someone to.
in the words of its author:
"The GPL prevents code from being sold by itself or as part of a larger
This is thoroughly false. There is no restriction on selling GPLed
software; from the FSF GNU GPL FAQ:
"Does the GPL allow me to sell copies of the program for money?
Yes, the GPL allows everyone to do this. The right to sell copies
is part of the definition of free software. Except in one special
situation, there is no limit on what price you can charge. (The one
exception is the required written offer to provide source code that must
accompany binary-only release.)"
"However, it leaves the door open for the authors to commercially sell
the code under different licensing terms if they so choose.
For example, this can easily occur:
1. a single author may initially release code as GPL;
2. the author later decides that the code has commercial viability;
3. the author stops distributing the code with the GPL.
4. the author then reissues the exact same code with a fee-based
What does this mean? It means that the GPL is a nice hedge for an author
or organization who wants to reserve the exclusive right to commercially
sell the software at some future point without competition."
This argument is expanded on in some detail; but relies on two
misinterpretations of the GPL:
1. An author is certainly free to sell his/her code while it is under
the GPL. As is anyone else, there simply is no "right to sell the code
exclusively" in the GPL, see above.
2. As the copyright holder, I believe the author is certainly free to
change his/her license with a future release -- regardless of whether
the code had changed. But even if all reference to the GPL were removed
from the future release, that would not revoke earlier releases' GPL
licenses; anyone who cared to could fork a GPL release and continue
development provided they used the GPL license. Thus the GPL achieves
the one thing the author of this article attributes as the benefit of
the MPL: a free market incentive to keep software free.
His next argument is with the "viral" nature of the GPL, but his first
point supporting the argument is not true:
"First, it prevents the use of code released under other Open Source
licenses, with the exception of Public Domain, from being used in
combination to create a larger work. For example, suppose that you have
located a third of the source code components that you need for your
project under the GPL, another third under the X consortium/MIT style
licenses, and the final third as Public Domain. Problem solved? No, you
will either have to rewrite the GPL or the X consortium/MIT components
as GPL will not co-exist with the other."
From the top of http://www.gnu.org/philosophy/license-list.html:
"We classify a license according to certain key questions:
* Whether it qualifies as a free software license.
* Whether it is a copyleft license.
* Whether it is compatible with the GNU GPL. (This means you can
combine a module which was released under that license with a
GPL-covered module to make one larger program.)"
In fact his X11/MIT example is listed as compatible with the GPL on that
page; I can't say whether this has changed since 1999, when this article
was written, but it is clearly wrong today.
Last he complains that the GPL effectively creates a gulf between
proprietary developers and FOSS developers... this certainly was an
issue for a lot people in 1999, but I don't consider it important enough
anymore to bore the list further
btw, I am a big fan of Mozilla, & had never bothered to read up on their
license. I see a version 1.1 (which presumably came out since that
article was written) can, under certain conditions be compatible with
the GPL -- at least according to the FSF:
"MPL 1.1 has a provision (section 13) that allows a program (or parts of
it) to offer a choice of another license as well. If part of a program
allows the GNU GPL as an alternate choice, or any other GPL-compatible
license as an alternate choice, that part of the program has a
I certainly don't believe that the GPL is best for everyone, and if your
main issue with the GPL is its viral nature, the MPL looks like it may
be a good alternative, after the LGPL & X11 licenses
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