Microsoft's Dfs

[Bill Studenmund]

On 30 May 2002, Simo Sorce wrote:

> On Wed, 2002-05-29 at 21:46, David W. Chapman Jr. wrote:
> > I don't think this will be a problem.  We currently have a GPL math
> > emulator in our kernel, just not enabled by default
> >
> > options         GPL_MATH_EMULATE        #Support for x87 emulation via
> >                                         #new math emulator
> >
> > If it can be loaded as a kernel module it will be even less of a
> > problem, but I don't know the specifics about the program in question.
>
> Uhmm that's not entirely true.
> There is a problem. When you distribute a kernel in which that module
> has been linked (statically or dynamically) you have to release the
> whole kernel under the GPL terms if you distribute it in binary form
> (you must distribute the source of the whole kernel or offer a written
> offer to give the source at no cost but that of the medium).

You are incorrect with regards to dynamic linking. It is perfectly fine to
distribute a FreeBSD kernel (with whatever manner of drivers & subsystems,
closed or open source) and then link in a GPL'd module at run-time.
Assuming the GPL'd module isn't needed for the primary functioning of the
kernel. i.e. the GPL'd module isn't the VM system or the only file system,
and you're not trying to make a GPL'd program not GPL'd by calling it a
module.

RMS was asked about this directly a number of years ago, and agreed in the
affirmative.

> not doing so or offering only the GPL code part as source would be a
> copyright violation of the owners of the code of the module.

You are not correct on that point. You will have to distribute the source
of the GPL'd module, and any modules that depend on it. But you won't have
to release source for the whole kernel.

The essential point is that the GPL governs distributing mixed binaries.
It does not say that GPL'd and non-GPL'd bits can't be mixed, just that
they can't be mixed and distributed. With dynamic linking, the mixing
happens in the target computer (and in principle happens every boot).

While there are a number of issues and potential concerns regarding the
GPL and its impact on other code, this is not one of them.

Take care,

Bill