Real-Time Operating System (RTOS)

Very nice blog on RTOS: https://www.linkedin.com/pulse/my-2-years-qnx-heres-what-ive-learned-winston-leung-uzl4c/?trackingId=6tV3sWTvEqahXZFyI1wIAA%3D%3D

What is Real-Time Operating System?

That is an excellent question, and the answer is not clear.

The term Real-Time Operating System (abbreviated as RTOS) has been applied to a wide variety of foundational software that is intended to support the execution of applications with strict timing requirements (for example industrial controllers or audio streaming). On the one extreme the term has been used for simple executives into which the application code is added to create a single program running on a basic micro-controller. On the other extreme are complete UNIX and UNIX-like operating systems with real-time capabilities, executing on complex multi-processors with large amounts of memory and many peripherals. The QNX RTOS belongs to the latter class.

A computer that only runs one program does not require an operating system, as the program can monopolize all resources without any adverse consequences. This is the case for many micro-controllers, even those that perform multiple, complicated tasks. Such a control program may be built together with some additional code that provides routines for accessing the hardware and scheduling the various tasks, but that does not make that code a true operating system.