QNX is a real-time operating system designed for critical embedded systems. It is a commercial Unix-like microkernel OS primarily used in industrial, medical, automotive, and telecommunications devices. Some key features of QNX include high reliability, determinism, small memory footprint, and ability to scale from single-core to multi-core processors. The latest version, QNX Neutrino RTOS, has various safety and security certifications making it suitable for applications with functional safety and security requirements.