Xenomai

Xenomai is a real-time operating system (RTOS) framework co-located with the Linux kernel. Its primary goal is to enable the development of applications with stringent real-time requirements alongside general-purpose Linux applications on a single system. Xenomai does not replace the Linux kernel, but rather extends it to provide real-time capabilities.

Xenomai achieves real-time performance by employing a dual-kernel architecture. It introduces a small, dedicated real-time kernel (the "nanokernel") that runs alongside the standard Linux kernel. The nanokernel directly manages time-critical tasks, providing them with guaranteed latencies and preemption capabilities.

The Linux kernel effectively becomes the idle task for the real-time kernel. When a real-time task needs to run, the nanokernel preempts the Linux kernel, allowing the real-time task to execute immediately. This mechanism allows applications to meet deadlines and achieve deterministic behavior.

Xenomai provides a variety of real-time APIs (Application Programming Interfaces) that developers can use to create real-time tasks, manage synchronization, and handle interrupts. These APIs offer different programming models, including POSIX threads (pthreads), RTDM (Real-Time Driver Model), and native Xenomai API.

Xenomai is typically used in applications where predictable timing is crucial, such as industrial automation, robotics, data acquisition, and audio/video processing. It allows developers to combine the benefits of a real-time operating system with the flexibility and extensive ecosystem of Linux.

Xenomai is an open-source project, actively maintained and supported by a community of developers. It is licensed under the GNU General Public License (GPL).