Well how much work can you expect a for-profit-company to do in order to release their software as open source? They choose a licence that worked for them, then and there because of reasons. This included the work on ZFS.<p>There are operating systems that have licences that permit the ZFS code in the kernel. What reasons did SUN have to specifically block the Linux kernel but not BSD &#x2F; Darwin ? The choice of license has everything to do whit what license SUN was comfortable using and nothing to do with keeping GNU&#x2F;Linux out of the party.<p>If the answer is that a lot of their competitors at the time were invested in GNU&#x2F;Linux and thus could not use their code, that is a very short sighted move.