A Real-Time Operating System (RTOS) is an operating system designed for real-time computing applications that process data and events with critically defined time constraints. An RTOS is distinct from other operating systems in that it is designed to guarantee a soft or hard performance category, rather than high throughput. An RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically, it is a hard real-time OS.
An RTOS has two key features: predictability and determinism. In an RTOS, repeated tasks are performed within a guaranteed time frame, and the system is designed to execute its tasks quickly and effectively. RTOSes are frequently used in critical systems where failures can have catastrophic consequences, such as robotics or flight controllers, and they must have higher security standards and more reliable safety features.
RTOSes are used in environments where a large number of events, mostly external to the computer system, must be accepted and processed in a short time or within certain deadlines. Such applications include industrial control, telephone switching equipment, flight control, and real-time simulations. The processing time in an RTOS is measured in tenths of seconds, and the system is time-bound with a fixed deadline. The processing in this type of system must occur within the specified constraints; otherwise, it will lead to system failure.
The advantages of real-time operating systems include maximum utilization of devices and systems, which results in more output from all the resources. The RTOS needs to be of high quality and easy to use, and the developer must be able to rely on it, supported by in-depth training and good, responsive support.
