QNX operating system - open source.

QNX is one of the Microkernel based embedded real time operating system, now a days am looking into. I just come to know from its site, it is become for open and through their community development site, calling it as Foundry 27, you can get the CoreOS, Core Netowrking, Drivers and BSP related source code.

And its having Hybrid model of License, unlike GPL2, if you want to give it back to community for Open, you can, otherwise you can keep it for your commerical.

http://licensing.qnx.com/developer-licenses

For core os, see the link,

http://community.qnx.com/sf/projects/core_os

For the core networking, see the link

http://community.qnx.com/sf/projects/networking

For the core file systems, 

http://community.qnx.com/sf/projects/filesystems

-srinivas.