Note: The opinions expressed here are my own and have no relationship with the opinions or official viewpoints of any organization with which I am associated
We believe that Linux is, in material part, an unauthorized derivative of UNIX.
It has certainly taken them a long time to come to that conclusion, and they offer no evidence. Instead, they resort to conjecture:
Many Linux contributors were originally UNIX developers who had access to UNIX source code distributed by AT&T and were subject to confidentiality agreements, including confidentiality of the methods and concepts involved in software design. We have evidence that portions of UNIX System V software code have been copied into Linux and that additional other portions of UNIX System V software code have been modified and copied into Linux, seemingly for the purposes of obfuscating their original source.
Conjecture? Yes, but what about the evidence? Well, if they have evidence, why don't they show it? And how important is this code anyway? Ten years ago, USL sued BSDI for incorporating UNIX source code in BSD/386. Considering that BSD/386 is a UNIX derivative, that's not unreasonable, and in fact some code was found that slipped through the cracks. It's not exactly the kind of code that would make any difference, though; in fact, it could almost be argued that, given the data structures, it was accidentally rewritten. Here's an example
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