[pilgrim689]

I was going to mention safety certification[1], but if you're saying we should disregard those, then I'm not sure what you're looking for. QNX was built with real-time and safety-critical constraints in mind. Linux was not. I'm not saying QNX is generally better than linux... just that if I want to browse the web at home I'd use Linux, and if I want a kernel to control the car I drive I'd choose QNX.

[1] http://www.qnx.com/products/neutrino-rtos/safe-kernel.html

[javert]

AFAIK, the kind of safety certificaitons applied to RTOSs are all about development process, and have nothing to do with actually proving correctness in a "mathematical" sense. I know very little about IEC 61508, but for DO-178B/C, it is all about development process. No certification agency wants to claim that software is actually correct, because they can't actually show that, and then they'd be blamed if something bad happened.

I have talked to people in the preempt_rt Linux community that believe Linux will come to dominate the RTOS market just like it has a lot of other stuff, and I think they have a compelling argument. Once preempt_rt is mature enough, it's hard for me to see any reason for going with something like QNX.

[javert]

> Once preempt_rt is mature enough, it's hard for me to see any reason for going with something like QNX

To correct myself: except that the Linux development process is not compatible with current cerfitication standards. Despite that, it's possible that the Linux dev process is more mature and better "tracked", and just better, than what the certs actually require, so it may eventually be possible to certify it somehow. (Anyone with thoughts on this, please pipe up...) I get the impression that some preempt_rt people have looked into this.