Just went through the Xenomai API doc. Nothing out of the ordinary there. Timers, queues, shared resource management, task management, memory management and pipes to linux. http://www.xenomai.org/documentation/branches/v2.4.x/html/api/index.html Adeos: a nanokernel HAL intended to run several OS kernels together. It implements a queue of signals to be sent to each kernel in sequences. Used to run Xenomai's kernel + Linux together. RTDM: Real Time Driver Model. Works for Xenomai and RTAI.