| To GPL 3 or not to GPL 3, that is the Linux question |
Feb. 01, 2006
Linus Torvalds made it clear on January 25th in a message to the Linux Kernel Mailing List (LKML), that as far as he was concerned, the Linux operating system is going to stay under General Public License 2 and not migrate to GPL 3. Discussion of the matter, however, has not come to an end.
Richard M. Stallman, primary author of the GPL and founder of the Free Software Foundation (FSF) isn't interested in fighting with Torvalds over the matter.
"I don't want to have an argument with him about this," Stallman said.
Instead, Stallman simply said, "The Linux developers can decide whether to allow use of Linux under GPL version 3. This won't directly affect other parts of the system."
As for code signing, an issue that Torvalds takes exception to, Stallman's not quite clear on what it is that Torvalds doesn't like.
"If you mean keys that developers use for signing source releases, GPL v3 says nothing about them," said Stallman.
He explained, "The only kind of signing keys that GPL v3 has rules about are keys for signing a binary so that a machine will execute it. GPL v3 would require the maker of a TiVo-like device that you bought to give you the key, so you can sign your modified versions and make them run. They would not have to publish this key, but they would have to give it to you."
While Stallman is content to let the Linux development community decide what to do, there is dissent within that community about what to do about GPL 3.
Since the discussion began on the LKML, the primary discussion group of Linux kernel developers, it has not died down even though Torvalds has made his position clear.
Torvalds insists that Linux itself makes it clear that it is covered by the GPL 2, and no other versions of the license: "We've always said which license explicitly. It's in the COPYING file." However, others disagree.
If it were simply newer, less experienced members of the Linux development community, this might not matter that much. As it happens, though, one of the people who believes that there is still some doubt about whether Linux is covered by the GPL 2 alone is Alan Cox, a leading Linux developer.
Cox is not a GPL 3 supporter per se. In an LKML message dated January 20th, Cox wrote, "What finally happens is going to depend almost entirely on whether the GPL v3 is a sane license or not and on consensus, and it is *way* too early to figure that out."
But, Cox also doesn't believe that the Linux kernel code that Torvalds has been discussing has ever explicitly been placed under the GPL 2. Cox wrote to the LKML on January 30th that, "Merely adding the copying file likewise is still not specifying a version. You may be *implying* one but that is not specifying."
This prompted Torvalds to fire back, "Alan, you're weasel-wording, and making up arguments that aren't valid."
Torvalds continued, "At no time has Linux ever been distributed [with] the version of the GPL that it is distributed under being in any question at all. THAT is my argument."
Further, Torvalds insists that "the fact is, the kernel is not licensable under GPLv3 without tons of work. Work that I'm not in the least interested in doing, or even helping with."
If this sounds like the license equivalence of arguing over how many angels can dance on the head of a pin, some Linux developers would agree.
Theodore Ts'o, a core Linux kernel developer, asked on February 1st for the community to "give this thread a rest, OK?"
"Whether or not Linux is licensed under the GPLv2 only or not is ultimately a matter for the lawyers," continued Ts'o.
A matter of greater concern to Ts'o is whether or not GPL 3 will be compatible with GPL 2.
"The one big problem I see with the GPLv3 effort is given the additional restrictions regarding DRM, it doesn't seem to clear to me whether a project which has even a single line of GPLv2-only code can accept GPLv3 code. That is, GPLv3 is designed to be compatible with more licenses, but that doesn't matter of GPLv2 isn't compatible with GPLv3. If that is the case, if only a single person (like Rogier) has I want GPLv2-only, the whole project ... can't use any GPLv3 code unless they are willing to track down and rewrite all of the code written by that person or persons," said Ts'o.
At the same time, the fact that GPL 3, in its current draft, is more compatible with other open-source licenses is what other open-source developers find interesting about it.
As Simon Phipps, Sun's Chief Open-Source Officer, explained recently, the "lack of a patent assignment in GPL v2 means people could circumvent the patent pooling if they opt for GPL, but the patent grant in GPL v3 looks good, even if the patent piece is a bit thin."
Because of this, and other clauses, Sun is considering dual-licensing its OpenSolaris under its own CDDL (Community Development and Distribution License) and the GPL 3. Were Linux to be placed under the GPL 3, this would make it possible for code to be shared between the two open-source operating systems.
At this point though, despite the arguments on the LKML, Torvalds remains firmly behind a GPL 2 only license for Linux -- now, and in the future.
As the GPL 3 continues on its evolutionary path towards acceptance, we can only be sure that the debate over its restrictions and its uses in Linux will only continue.
--Steven J. Vaughan-Nichols
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