Real-time operating system

Computer operating system for applications with critical timing constraints

A real-time operating system (RTOS) is an operating system (OS) for real-time computing applications that processes data and events that have critically defined time constraints. An RTOS mainly targets resource constrained devices like microcontrollers. It is distinct from a time-sharing operating system, such as Unix, which manages the sharing of system resources with a scheduler, data buffers, or fixed task prioritization in multitasking or multiprogramming environments.

From Wikipedia, under CC BY-SA. More on occurri.