Decision: CC-BY / GPL
dcarrera at math.umd.edu
Fri Mar 11 07:04:02 EST 2005
Branko Collin wrote:
> "part" --> "party"?
> There was some discussion about dual licensing in the past (look at
> the archives).
That's interesting. About the ShareAlike license not being compatible with
dual licensing. I wonder why the same thing doesn't happen with the GPL.
Well, in any event, thanks for the note. I'll be careful not to use the SA
unless I know what I'm getting into.
> "My (admittedly inexpert) understanding is that a dual-licensed
> derivative work would not meet the requirements of by-sa 1.0,
If it's your own work, you can slap any license you want on it. Including
a dual SA/FDL. But what this person wrote suggests that the licensees will
be forced to pick one or the other.
But I still wonder, why doesn't that happen with the GPL ?
But in any event, I don't have to think about this. I'm not going to use
the SA license.
> Although strictly speaking you are not dual-licensing it, it seems
> like you are forcing any down-stream authors to choose between CC-BY
> or GFDL
I checked the language of the Perl license, and they wrote it the same
way. They say "or". And people have been re-distributing Perl using both
licenses at the same time for 20 years. And almost all the modules on the
CPAN archive do the same.
IANAL, but I figure that the laguage is okay. This is my interpretation:
Suppose I gave you two copies of the file. One under the GPL and one under
the CC-BY. Then you have both licenses. You can then give the unmodified
file to someone else, under either license. Or you can give them two
copies, one under each. In practice, so far, you are still handing out the
file with both licenses.
Now, what happens if you make a modification? Well, suppose the
modification is compatible with both licenses? Then you still have
permission to distribute it under the GPL, and you *also* have permission
to distribute it under the CC-BY. So, you can still give out two copies of
the file, one under each license.
So, it looks like, as long as the modifications you make are allowed by
both licenses, you can, in effect, treat the license tandem as one unit.
You only lose this when you want to do something that is allowed by one
license and not the other.
So, it seems to me that dual licening really does work.
Daniel Carrera | I don't want it perfect,
Join OOoAuthors today! | I want it Tuesday.
More information about the cc-licenses