[Axiom-developer] Re: [open-axiom-devel] [fricas-devel] umlaut in Guess - mailing list for algebra

[Bill Page]

On 9/4/07, Alfredo Portes wrote:
> Bill Page asked:
> > Would this mean that Guess could not be included in any of the
> > existing Axiom forks (which are all licensed under modified BSD)?
>
> But I was under the assumption that modified BSD is compatible with GPL.
>

Yes that is definitely true: modified BSD *is* compatible with GPL.
Sometimes all this licensing nonsense is hard to get your head around.
Here is how I understand it:

One of the defining characteristics of GPL is that *if* you
incorporate *any* source code from some other package that is licensed
under GPL into some new product - _whatever the license of the
original code_ - *then* the entire derived work must be licensed under
GPL. That is what is meant by saying that GPL is a "viral license" and
that it "infects" the otherwise compatible licenses of other software
packages. (Of course people who phrase things this way usually intend
to cast GPL in an apparently negative light.) But this is a deliberate
feature of GPL to which some people object and other people applaud.
It all depends on how you think open source licensing and free access
to source code is best promoted.

Actually this kind of "infection" is not such an unusual thing. For
example: modified BSD is also compatible with Aldor's new APL2
license. Incorporating Aldor into Axiom in such a way that Aldor was
*required* in order to build Axiom would have a similar affect of
"infecting" Axiom with Aldor's "non-commerical uses only clause". The
difference is that GPL requires infection to occur even in the case
when the GPL software to be included is not an integral and essential
part of the combined package.

So in this case, if Martin's GUESS code is licensed under GPL and it
is added permanently to any of the AXIOM distributions that are
normally licensed under modified BSD, the license of the combined
result must be GPL. Since it is apparently the intention of the Axiom
distributions to remain licensed under modified BSD, this means that
GUESS could not be included in any of these Axiom distributions. But
in any case this "infection" has already occurred for those Axiom
distributions that require certain GCL components (unexec,bfd and
xgcl). So maybe this is not such a big deal when all is said and done.

I am sorry to be so pedantic and possibly annoying to some people but
I hope that what I am saying makes sense.

Regards,
Bill Page.