Course Overview

A Real-Time Operating System (RTOS) is a computing environment that reacts to input within a specific time period. A real-time deadline can be so small that system reaction appears instantaneous. The term real-time computing has also been used, however, to describe “slow real-time” output that has a longer, but fixed, time limit. Learning the difference between real-time and standard operating systems is as easy as imagining yourself in a computer game. Each of the actions you take in the game is like a program running in that environment. A game that has a real-time operating system for its environment can feel like an extension of your body because you can count on a specific “lag time:” the time between your request for action and the computer’s noticeable execution of your request. A standard operating system, however, may feel disjointed because the lag time is unreliable. To achieve time reliability, real-time programs and their operating system environment must prioritize deadline actualization before anything else. In the gaming example, this might result in dropped frames or lower visual quality when reaction time and visual effects conflict.