The LynxOS RTOS is a Unix-like real-time operating system from LynuxWorks (formerly "Lynx Real-Time Systems"). Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility. LynxOS is mostly used in real-time embedded systems, in applications for avionics, aerospace, the military, industrial process control and telecommunications.
Full Memory Management Unit support has been included in the kernel since 1989, for the reliability of protected memory and the performance advantages of virtual addresses. ARM and PowerPC architectures are also supported.
LynxOS components are designed for absolute determinism (hard real-time performance), which means that they respond within a known period of time. Predictable response times are ensured even in the presence of heavy I/O due to the kernel's unique threading model, which enables interrupt routines to be extremely short and fast.
LynuxWorks holds a patent on the technology that LynxOS uses to maintain hard real-time performance. Patent #5,469,571 was granted to LynuxWorks November 21, 1995: "Operating System Architecture using Multiple Priority Light Weight kernel Task-based Interrupt Handling."
Memory Management Unit (MMU) support resides at the lowest level of the LynxOS kernel. Full MMU support, included in the kernel since 1989, provides the reliability advantages of protected memory and the performance advantages of virtual addresses.
In 2003, LynuxWorks introduced a specialized version of LynxOS called LynxOS-178, especially for use in avionics applications that require certification to industry standards such as DO-178B.
The Usenet newsgroup comp.os.lynx is devoted to discussion of LynxOS.