RTAI

RTAI, abbreviated from real-time application interface, is a real-time extension for the Linux kernel, which lets users write applications with strict timing constraints for Linux. Like Linux itself the RTAI software is a community effort. RTAI provides deterministic response to interrupts, POSIX-compliant and native RTAI real-time tasks. RTAI supports several architectures, including IA-32 (with and without FPU and TSC), x86-64, PowerPC, ARM (StrongARM and ARM7: clps711x-family, Cirrus Logic EP7xxx, CS89712, PXA25x), and MIPS.

RTAI consists mainly of two parts: an Adeos-based patch to the Linux kernel which introduces a hardware abstraction layer, and a broad variety of services which make lives of real-time programmers easier. RTAI versions over 3.0 use an Adeos kernel patch, slightly modified in the x86 architecture case, providing additional abstraction and much lessened dependencies on the "patched" operating system. Adeos is a kernel patch comprising an Interrupt Pipeline where different Operating System Domains register interrupt handlers. This way, RTAI can transparently take over interrupts while leaving the processing of all others to Linux. Use of Adeos also frees RTAI from patent restrictions caused by RTLinux project.

RTAI-XML is a server component of RTAI, implementing a service-oriented way to design and develop real-time (RT) control applications.

This project was born to fulfill the needs of a university group, mainly focused to have a flexible platform for learning control systems design, allowing the students to test their programs remotely, over the Internet. Leaving the first wishful thinking and going to the real implementation gave rise to the alpha version of RTAI-XML, that showed the potential impact of the basic idea of a net separation of hard and soft real-time tasks in the programmation logic. What was necessary to assure that students could not crash the RT process, is now becoming a new RTAI paradigm.