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I keep hearing that the GPL and CDDL are incompatible. But repeating something doesn't make it true. And I have read both licenses, and have come to the conclus
by l1ambda 9y ago
I keep hearing that the GPL and CDDL are incompatible. But repeating something doesn't make it true. And I have read both licenses, and have come to the conclusion that they're unlikely to be incompatible in the first place. Unfortunately, every time this line of argument come up, it tends to get buried in discussion.
The basis of the incompatibility claim seems to be from 3 arguments:
1) Statements from the FSF website, but those have no legal bearing against the actual text of the licenses
2) Claims that the CDDL was engineered to be incompatible with the GPL, again, it's an interesting hypothesis but has little bearing against the actual text of the licenses
3) Derivative Work argument from the GPL. This seems to be the only one that could hold water; however, I doubt that a court would find ZFS to be derivative work of the Linux kernel.
Furthermore, even if you argue that the "derviative work" clause makes them incompatible, there’s no way actually to prosecute such a violation. Copyright law is something called a tort in law, which means you have to show that someone violated the rules AND also caused quantifiable harm. What would our theory of harm be? (https://blog.hansenpartnership.com/are-gplv2-and-cddl-incompatible/ https://blog.hansenpartnership.com/are-gplv2-and-cddl-incomp...)
- saurik 9y agoFWIW, Canonical's legal analysis also concluded the licenses were not incompatible in this instance (though potentially for very different reasons than you do). http://blog.dustinkirkland.com/2016/02/zfs-licensing-and-linux.html http://blog.dustinkirkland.com/2016/02/zfs-licensing-and-lin... (edit: When I wrote this comment, the person I was responding to had only left a relatively short comment, without the argument or the subsequent bullet points.)
- LukeShu 9y agoThey didn't conclude that the licenses were not incompatible, they concluded that ZFS for Linux is not sufficiently based on the Linux kernel for the licenses to interact.
- l1ambda 9y agoTheir conclusion was that zfs.ko, as a self-contained file system module, is not a derivative work of the Linux kernel but rather a derivative work of OpenZFS and OpenSolaris.
- jsiepkes 9y agoThis is the biggest weakness of the GPL IMHO. The fluffy wording which is sometimes so vague only a court can really tell if something is allowed or not. For example the GPL talks a lot about linking. Now how does that work with languages where there is no linking at build time (like Java)? The GPL's architects tells us that doesn't matter because its all in the same spirit. But that's just an opinion, you need a court to rule on that to be sure.
- user5994461 9y agoThe judgement to settle the compatibility will take years and could go either way, costing billions of dollars to either company. Risks are sky high and no sane company should invest in it. It's worse than being just incompatible.
- mastax 9y ago>The judgement to settle the compatibility will take years and could go either way, costing billions of dollars to either company. Who would the suit be between? Oracle and Canonical? >Risks are sky high and no sane company should invest in it. It's worse than being just incompatible. Companies don't seem to have a problem using Nvidia's binary kernel driver so I doubt it.
- boomboomsubban 9y agoI don't think the CDDL gets breached when the two get combined, so Oracle is unlikely. Any Linux contributor could sue though.
- deleted 9y ago[deleted]
- user5994461 9y agoOracle, RedHat, IBM, Google, Facebook. Any telco or embedded hardware manufacturer who has significant revenues and ship their own Linux/Unix derivatives. Canonical is the smallest company, it has the least to lose.
- temprature 9y agoActual lawyers have also read both licenses and came to the conclusion that they are incompatible: https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ The main debate over the incompatibility isn't about GPL vs CDDL; even Canonical isn't arguing that the licenses aren't incompatible. It's specifically about the Linux kernel vs ZFS; ie. does linking the ZFS module with the Linux kernel make the ZFS module a derivative work of the Linux kernel. If yes, it has to be able to have the GPLv2 applied to it, which it can't. If no, then the incompatibility is irrelevant, and the kernel and ZFS can be distributed together and under their own separate licences. This is where opinions (by legal experts, not people on the internet) differ, the FSF and SFC's lawyers say this makes ZFS a derivative work and you can't distribute them together, Canonical's lawyers say it doesn't and therefore you can.
- LeoPanthera 9y agoI'm surprised there isn't a one-click way for the user to build their own kernel with ZFS inside it. As long as I don't distribute the resulting binary there should be no legal implications.
- greenhouse_gas 9y agoThere is (at least on Debian) - enable contrib and use apt. The problem is that neither your install or recover CD won't have it enabled by default, so if you have a problem, your hard-drive won't mount.
- exikyut 9y agoSo extend the script to build you a recovery ISO or USB image too, and then insist that you reboot and test the recovery image.
- boomboomsubban 9y agoOr install ZFS from your live recovery instance and load the mod. Not a big problem.
- dmm 9y agoThe CDDL release announcement[0] says: """ Thus, it is likely that files released under the CDDL will not be able to be combined with files released under the GPL to create a larger program. """ So the creators of the CDDL didn't think they were compatible. What do you mean when you say "have come to the conclusion that they're unlikely to be incompatible"? Do you believe one could combine the Linux kernel and ZFS into a single source tree and distribute binaries under the terms of the GPLv2? [0] https://lwn.net/Articles/114840/ https://lwn.net/Articles/114840/