A single unified license
A number of people have raised issues about the GFDL that pertain to
converting documentation into software and vice versa. They call for
software and documentation to be a single pool of material with
That goal goes way beyond what I aimed for when writing our licenses.
I wrote the GNU GPL as a license for software, and wrote other
licenses for documentation. I did not try to make software licenses
cover documentation or vice versa. The needs in these two areas are
different, so the licenses are often different--and incompatible.
For instance, here is the license we used for most GNU manuals before
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Foundation.
Nobody here would deny that this is a free documentation license. It
has the advantage of brevity, but in terms of merging the material
into a GPL-covered program, there's no difference between this license
and the GFDL. Both are incompatible with the GPL.
I designed the GPL to be license for free programs: it provides the
necessary freedoms for using programs as programs. If you want to
print the same material as a book, you can, but you run into practical
inconveniences--for instance, the requirement to distribute
machine-readable source code does not fit well with the way books are
published. The GPL can be used on documentation files, but it wasn't
designed for manuals.
Likewise, I designed the GFDL to be a license for free manuals: it
provides the necessary freedoms for using manuals as manuals, and
tried to attract commercial publishers to publish free manuals (though
none was interested in doing so at the time I wrote the GFDL). That
job was hard enough; I did not undertake to make it a suitable license
for software as well.
The goal that people are now proposing is much more ambitious:
essentially, to have a single license scheme that covers both software
and documentation. The benefit of this would be to combine two
separate information commons into a single larger one. This commons
would not include all free software, nor all free documentation; TeX
and Apache would not be part of it, nor would free manuals published
under the simple license above. The change would nonetheless be an
It is not a straightforward or easy job, however. To design a license
that is good for both free software and free documentation, and that
is close enough to today's GPL that it qualifies as a successor
version, may or may not be possible. In any case, it will take a lot
I intend to make the effort some day, but first I have to finish GPL
version 3, which faces other difficult questions.