Xenomai is a realtime development framework cooperating with the Linux kernel in order to provide pervasive, interface-agnostic, hard realtime support to userspace applications, seamlessly integrated into the GNU/Linux environment. Xenomai is based on an abstract RTOS core, usable for building any kind of realtime interface, over a nucleus which exports a set of generic RTOS services. Any number of RTOS personalities called "skins" can then be built over the nucleus, providing their own specific interface to the applications by using the services of a single generic core to implement it.
