Introduction to RTOS Part 1 - What is a Real-Time Operating System (RTOS)? | Digi-Key Electronics

A real-time operating system (RTOS) is an operating system that runs multi-threaded applications and can meet real-time deadlines. See this article to read more about them: An RTOS is often a lightweight operating system (OS) designed to run on microcontrollers. Much like general purpose operating systems, they offer a scheduler to run multiple threads or tasks, resource management (such as file I/O), and device drivers. An RTOS is necessary when embedded engineers need to run several threads at the same time on a processor. The “real-time” part of an RTOS means that such software can meet real-time deadlines. Note that this does not mean “fast,” but rather, it can guarantee that task execution time can be calculated prior to runtime. Embedded programmers often use a “bare-metal” or “super loop” structure instead of an RTOS when concurrency is not needed.