The Free Software Foundation has released the fourth or "last-call" draft of the third version of its GNU general public license, set a date for its official publication, and laid out reasons why the free and open-source software community should adopt GPLv3 sooner rather than later.
The GPL gives users the right to freely study, copy, modify, reuse, share and redistribute software. Created by Richard Stallman in 1989 for the GNU free operating system project, the license was last fully revised 16 years ago as GPLv2.
Besides releasing the fourth draft of GPLv3 on Thursday, the FSF also published an essay by Stallman extolling the benefits of moving from GPLv2 to GPLv3.
The new license deals with issues that have emerged recently, notably the patent-licensing deal around Suse Linux struck between Novell Inc. and Microsoft Corp. in November. Parts of the Linux operating system including its kernel are licensed under GPLv2.
Earlier this month, Microsoft executives created a firestorm of protest in the open-source community when they asserted that Linux and other open-source software infringe on 235 of the software vendor's patents.
"Microsoft made a few mistakes in the Novell-Microsoft deal, and GPLv3 is designed to turn them against Microsoft, extending that limited patent protection to the whole community," Stallman wrote. "In order to take advantage of this, programs need to use GPLv3." Software distributors who make discriminatory patent deals after March 28, 2007, may not pass on to others software covered under GPLv3.
Ultimately, the FSF would like to do away with software patents altogether, but realizes that is currently impossible, aiming instead with GPLv3 to ensure free software can't be made proprietary through patents, according to Stallman.
GPLv3 also deals with what Stallman terms "tivoization" or computers containing software covered by the license that can't be changed as well as DRM (digital rights management), which the FSF prefers to call digital restrictions management.
"Freedom means _you_ control what your software does, not merely that you can beg or threaten someone else who decides for you," Stallman wrote. "GPLv3 ensures you are free to remove the handcuffs. It doesn't forbid DRM, or any kind of feature. ... Rather, it makes sure that you are just as free to remove nasty features as the distributor of your copy was to add them."
The fourth GPLv3 draft draws on feedback the FSF received from the general public and official discussion committees on the previous draft that appeared in March. One of the key changes is around license compatibility between the GPL and open-source licenses. In the new draft, GPLv3 is now compatible with version 2.0 of the Apache License. The license also supports BitTorrent and contains language to make it more friendly to an international audience.
Previous drafts of GPLv3 were met with a mixed reception in the open-source community. In particular, Linus Torvalds, the creator of Linux, was highly critical of the first two drafts, but mellower about the third draft. Like other developers, he's previously stated he prefers to stick with GPLv2.
"GPL version 2 will remain a valid license, and no disaster will happen if some programs remain under GPLv2 while others advance to GPLv3," Stallman wrote. "These two licenses are incompatible, but that isn't a serious problem."
By incompatible, the FSF means that it sees no legal way to combine code licensed under GPLv2 with code under GPLv3. Such incompatibility is only an issue if developers want to link, merge or combine code from programs licensed under GPLv2 and GPLv3. "There is no problem in having GPLv3-covered and GPLv2-covered programs side by side in an operating system," Stallman wrote.
The FSF will take comments on the fourth draft for 29 days and plans to officially publish the final GPLv3 license on June 29.
The fourth draft of GPLv3 and Stallman's essay are on the FSF's Web site at http://gplv3.fsf.org/.