On Fri, Jul 23, 2010 at 7:23 PM, Platonides Platonides@gmail.com wrote:
I think that's because they are more liberal licenses, like MIT*. Do we have any code that isn't GPL-compatible?
*To which extent they can do that is debatable. Maybe they can only license under that license *some* pieces of their code.
There are at least some pages on mediawiki.org for extensions that are not under any open-source license at all. I remember at least one case where an extension there was only available as commercial software, and other developers in #mediawiki disagreed with my opinion that it should be deleted.
I consider that completely unrelated. PHP is a platform, similarly as how you can use a non-GPL program on a GPL kernel. Or write a document on a GPL text editor without it being automatically open source.
Insofar as PHP is just a program that processes input files, yes. But it also includes a standard library. If the PHP standard library implementation were licensed under the GPL, then at least according to the FSF's interpretation, it would be forbidden to write non-GPL programs for it. That's why OpenJDK (at the advice of the FSF) is GPL with a special linking exemption -- without the exemption, all programs written for it might have to be GPL. Likewise the GNU C standard library is licensed under the LGPL, not GPL.
Of course, in some of these cases there are non-GPL implementations too, and if you write it to be compatible with multiple implementations, I don't think anyone argues that it's a derivative work of any of them . . . I'm still not clear on this point. But in any event, I don't see why there'd be a difference between a library that happens to be shipped with a programming language implementation, and one that's not.
It wouldn't need to be under GPL. AFAIK, the case for that is that kernel drivers usually copy code from the GPL ones. Also note that since some version, they have apis not available for closed drivers.
I think there are some interesting discussions about this on lkml archives.
Linus Torvalds, at least, thinks that some drivers intrinsically need to be GPL:
http://lkml.indiana.edu/hypermail/linux/kernel/0312.0/0670.html
I don't know whether his view is correct, but it's certainly prevalent in the Linux kernel community, from what I've seen.