I've never used L4, sorry. But I do know that the two operating systems are completely unlike each other. L4 is a bare-bones hypervisor task/switcher kernel. QN

I've never used L4, sorry. But I do know that the two operating systems are completely unlike each other. L4 is a bare-bones hypervisor task/switcher kernel. QNX is a complete Unix, which is (to me) where all the value lies. How L4 compares with the QNX kernel, I don't have the knowledge to comment on.