On Jul 22, 2008, Antonio Olivares <olivares14031@xxxxxxxxx> wrote: > I do not understand here, why some licenses are compatible and which > ones are not. License compatibiliy analysis requires looking into the permissions and conditions established by each license, and looking for conflicts between them. For example, there's this funny Free Software license that is incompatible with itself: it says you can run, study, modify and distribute the software, with or without modifications, but you must distribute your modifications as patches to the pristine version of the file, rather than by distributing the modified version. So, if you take a program A and a program B, and you want to combine them, you can't do that, because both demand to remain as the baseline. A more common case of incompatibility is trying to combine two strong copyleft licenses: each license permits you to distribute the combination only under the license itself, so the only way you can satisfy both is if they're both the same license. Another common case is that of combining non-GPLed software with GPLed software. If the non-GPL license fails to grant some permission that the GPL grants, the combination cannot be distributed, because the GPL requires the combination to be distributed under the terms of the GPL, and doesn't permit distribution if you can't offer or pass on the permissions established in it for each and every part of the whole. > For instance, the Mozilla Public License is incompatible with the > GPL and we can see Mozilla firefox and/or Seamonkey, Thunderbird, > .., etc live nicely in several distributions Licenses apply to copyrightable works such as individual programs. Even a single package might contain code under different licenses, as long as the combination doesn't amount to a copyrightable work in itself. A distribution is a collection of programs. Although such a combination might be copyrightable in itself, and thus amount to a derived work, the GPL makes an explicit exception to combinations that are mere aggregations of packages in the same medium. This is clear permission for GPLed programs to be distributed along with programs under licenses incompatible with the GPL, as long as the programs are not derived works of the GPLed work. Or something like that, IANAL :-) > Also a project that was licensed under the GPL, made changes to > another license the CDDL, and I wondered why, GPL does not allow > those kind of things? If all the copyright holders of a program agree to offer the program under a different license, copyright law says they can do that. It doesn't invalidate licenses granted before, or commitments to grant such licenses, but they can stop offering the program under the old license and start offering it under the new license. Or they may start offering the program under both. Or offer it under some license to some parties, and under another license to other parties. -- Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/ Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org} FSFLA Board Member ¡Sé Libre! => http://www.fsfla.org/ Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org} -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
