uC/OS Real Time

µC/OS-III (Micrium's Operating System) is a real-time kernel for embedded systems. It provides task scheduling, synchronization primitives (semaphores, mutexes, message queues), memory management, and timer services. µC/OS is known for documentation quality (comprehensive books), certification readiness (for aerospace, medical, military), and deterministic, hard real-time guarantees. Owned by Silicon Labs, µC/OS is used in systems where missing a deadline is unacceptable: cardiac pacemakers, aircraft control, spacecraft, surgical robots. It's more complex and opinionated than FreeRTOS but offers production-grade reliability and support.