VxWorks and Linux for automation systems

I had some experiences with vxworks 10 years ago.

While the core kernel parts aren't too bad, a lot of the network code seemed to be 'tick-box' ports of code that would expect to run in a non-preemptive unix kernel with a defined user-kernel boundary to cross. this meant there was a LOT of missing locking.

Also while vxworks is expensive, the support (for real bugs) wasn't that good. I rather got the impression that the development group released software using a large trebochet, and that the support group were outside the wall. I had some binary patches I applied after loading the code, but it was almost impossible to get the fixes into the 'next version'.

The main problem with linux is the GPL.

Almost all the board code I've written (mostly network stacks of some form) runs without a commercial OS.