Tim Kelly <hockey@dialectronics.com> writes:

> > This is simply wrong. To make a somewhat extreme example, many drivers
> > in NetBSD were written or enhanced by looking at how Linux drivers for
> > the same hardware worked (and even say so in the CVS logs). If your
> > theory of derived works applies, then the entire NetBSD kernel is now
> > a derived work of GPL-licensed code and as such is subject to the
> > GPL. Do you believe this to be the case?
> 
> Yes.  Sounds like some people really screwed up and should be more
> careful about how they write drivers.  If NetBSD ever develops deep
> pockets, it won't go well.

So if one has ever looked at GPL'd software, one must be forever
forbidden from working on non-GPL software?

> In other words, you have no way of obtaining the knowledge for that
> hardware without looking at the Darwin code.

Knowledge about the hardware is simply not copyrightable. The
expression of that knowledge is, so I can't copy the comments out of
Apple's code that explain it, or the PDF that describes some other
part of their hardware, but having read the code or otherwise legally
figured it out, I may freely use it to write my own code.

        - Nathan