Well, it's definitely not FreeBSD -- that much I can say for certain. As far as any of us can tell, that's solely the network stack. I honestly expected Linux

Well, it's definitely not FreeBSD -- that much I can say for certain. As far as any of us can tell, that's solely the network stack. I honestly expected Linux with a custom userspace on top of it, and was quite surprised to see them continue with the custom kernel thing. We're not talking much about details of the lower levels yet (frankly, we just don't know enough to confidently do so, even if we wanted to put it all out there), but it's almost certainly a fork or (partial?) rewrite.