Personal tools

Patent shenanigans

From GPLv3 Wiki

Disclaimer: I am not a lawyer, and don't even play one in an MMORG.

Suppose I get a software patent, and then write software that uses it and release it licensed by GPLv3 (or any later version). It seems to me that the GPLv3 language has possible problems.

First, it appears to me that, unless I write otherwise, I retain the right to sue any user for patent infringement, since I'm the patent holder, and I'm not bound by GPLv3 because I'm the copyright holder. While I might not do that, I don't see that any downstream user can feel confident using the software. (This doesn't apply if I modify existing GPLv3 software to include functionality covered by the patent, of course.)

Second, suppose that the patent is transferred to another holder. This can happen voluntarily or involuntarily. For example, I could sell it, or it could be awarded to another party by a judgment, or I could go bankrupt, or I could die and leave it to my heirs. Assuming that I am bound by GPLv3, is there any restriction on patent enforcement suits from the party that now holds the patent?

Even aside from the case where I distribute the software in the mistaken belief that I have the right to sublicense freely, how safe is it to use patented techniques in GPLv3 software?

And what about this scenario: assume that there is a free software program X under the GPLv3, which is extended by company C to include patented algorithm P. C redistributes the modified X under GPLv3, thereby agreeing not to assert its patents against users and redistributors of the modified X. They are accepted back into the main development branch.

Unfortunately, the modifications were written rather badly, and over time other developers replace more and more parts of C's implementation of P with improved code until at some point, none of the original code is left, but algorithm P is still used. X is now no longer derived from C's original contribution(?), so that C is no longer bound by the non-assertion convenant with respect to X. Or is it?

--lourens 10:42, 3 October 2006 (EDT)