The issue isn't whether or not the code is open source / free software, it's specifically compatibility with the GNU GPL v2 under which the Linux kernel is released.
The GPL is picky about what licenses are compatible with it (or more specifically, what licensing terms), and for very good reasons given its intended purpose (to promote the availability of yet more GPLd code).
Which also exists in CDDL code. Viral copyright makes it real difficult to share things if various parties have different ideas as to how to best require others to share files.
The comparison at hand is with DTrace, which has afaik only Oracle as the copyright holder, so they could change the license if they wanted to.
CDDL is a bit weird. It's a free license that has a pointless restriction merely in order to make it GPL incompatible. Why people want to make things deliberately GPL incompatible is beyond me.
I'm looking through the source I have for DTrace, and there is code written by folks other than Oracle, so changing the license is more difficult than just that. Regarding the GPL, one must ask at the same time why the GPL makes itself deliberately incompatible with four-clause BSD code, or other Free licenses that predated the GPL. Viral licensing just leads to petty fiefdoms and precludes the very sharing they claim to protect.
oh boy, another GPL debate! phk was right, seems we never get tired of this stupid shit.
It didn't make itself "deliberately incompatible" with all free licenses before it, for example MIT/X11 is definitely compatible. Why is the original BSD license singled out?
Many people besides you believe proprietary software is harmful enough to enact defense mechanisms when proprietary software vendors harm the user and lock down free software into their products.
I singled out the original BSD license because it was extant and the GPL was not compatible with it. Such clauses are pretty common in the software world and give credit where credit's due; hell, Microsoft has no problem with it, why does it bind the panties of the average GPL supporter so much?
Furthermore, I'd argue that a lot of those defense mechanisms that copyleft supporters claim are necessary cause much more harm to Free Software than they do to proprietary software. The ability to use GCC for static analysis, for example, was muddied for many years by the GCC team's unwillingness to create a suitable API out of fear that it would become easier for proprietary software teams to use GCC without contributing. Meanwhile, proprietary compiler chains, like those Microsoft provided, were easily able to create those same tools because they were not driven by such fears. Additionally, you have statements from people like RMS trying to memory hole software ( http://gcc.gnu.org/ml/gcc/2001-02/msg00895.html ) that doesn't agree with his political views. While the goals may be noble, the route the free software community has chosen to get there has devolved into stubbornness and childishness to the detriment of everyone.
> I'm looking through the source I have for DTrace, and there is code written by folks other than Oracle,
That is irrelevant if DTrace used copyright assignment to ensure that there was always one copyright holder, regardless of the number or affiliations of contributors. I honestly don't know if they did or not, but from what I've heard in this thread it sounds like they did.
I think development has moved away from Oracle now partly, but at one point there was a Sun/Oracle only version. This piece [0] argues that the reason for not dual licensing it was that there might be GPL only contributions and then eventually a GPL fork, which is not that unlikely given the larger size of Linux vs VSD+Solaris. Same with ZFS I guess, even if Oracle mostly sponsored btrfs.
The GPL is the world's most popular license. The CDDL was purposely designed to be incompatible with it. Anyone choosing the CDDL is purposely choosing to exist in an island outside the GPL.
In as much as the metadata is accurate, the information can be interpreted in any meaningful way, and considering selection bias for things that people actually make available via these services (however, if something isn't listed with some index that makes it discoverable, it doesn't matter what the license is):
Sourceforge: of 1236 "OSI Approved" listed via the search refinement interface, 983 GPLv2, 22 BSD, 10 Apache 2.0, 8 MIT.
Unfortunately, neither Github or Oholo provide aggregated license information or it's not easy to find [0]. I did find this two year old post [1] about licenses of the most watched repositories on github, but popularity of the project isn't necessarily an indicator of popularity of the use of the license -- except as much as the type of license indicates which projects people will want to use because the the license lets them contribute. I do vaguely remember some random blog posts that attempted to do license counts in a repeatable and objective way, but my google-fu is failing me right now.
These are hardly conclusive numbers, and it becomes difficult to consider it in aggregate. Is all of OpenBSD considered one "project", as it's effectively distributed as one piece, or are the individual components themselves projects? Is everything in GNU core-utils one project? Maybe each binary counts as the use of the license. However, just going by these services' self-promoted "project" delineation being ~10x in favor of GPL (GPLv3, LGPL may or may not be included in the above numbers), the non-GPL licenses seem to be significantly low enough that "The GPL is the world's most popular license" may be a reasonably safe, even if not entirely accurate, position to take. I suspect that if you pick 10 projects at random, more than half of them will be GPL.
In addition to what thwarted posted, Black Duck is a great resource for analysis of open source software as they have a database drawn from all over the place: http://www.blackducksoftware.com/resources/data
If you summarize for GPL/LGPL and what projects are compatible, it winds up being about 45% of projects GPL/LGPL and up to 87% or more of all open source projects are compatible with the license. I go over it in a handy chart here: http://johnhaller.com/useful-stuff/open-source-license-popul...
As thwarted said, it can be problematic looking at 'projects' as something like bootstrap on github, which is MIT licensed, has over 24,000 forks. Now, most of those are nonsense and have no changes (or at least nothing useful) but do you count that as 24,000 projects?
Outside of CDDL being explicitly crafted to be incompatible with GPL, no action from FSF would have any impact on Linux licencing since Linus chose to use GPLv2 ONLY rather than 'GPLv2 or later' which is the usual case.
Beyond that, given how Linus himself thinks that 'Making Linux GPL'd was definitely the best thing I ever did. ' and him attributing it as being a huge part of why Linux became such a success, I'd say there would zero chance of a Linux license change even if it was all up to Linus, which of course it is not.
