You missed a pretty big part here. OpenZFS and Nvidia are modules of the kernel, they use the exposed API. OpenZFS is fully open source, with an incompatible l

You missed a pretty big part here. OpenZFS and Nvidia are modules of the kernel, they use the exposed API. OpenZFS is fully open source, with an incompatible license. Nivida's graphic driver has a GPLed portion that it's binary blob loads into. OpenZFS is may be only considered derivative, because when it compiles, it has to include the kernel header files, because that is how you compile C code. No part's of its code base infringe on linux's and no part of linux's code base infring on OpenZFS's. Just the compile binary might be infringing. However this has implications that are far reaching, as if this is considered derivative. GLIBc is GPL, does that mean everything compiled against GLIBc are derivative of GLIBc? If so, this means a great many things are legal required to be GPLed and code shared. Back on topic, in the case of VMWare, the claim is that they are actually using GPLed linux code in their code. Much more than using the exposed API. This one should be an open shut case.