An Introduction to RTOS

Abstract

RTOS (real time operating system) can be defined as “The ability of the operating system to provide a required level of service in bounded response time.” A real time system responds in a (timely) predictable way to unpredictable external stimuli arrivals. To build a predictable system, all its components (hardware & software) should enable this requirement to be fulfilled. Traffic on a bus for example should take place in a way allowing all events to be managed within the prescribe time limit. However it should not be forgotten that a good RTOS is only is building block. Using it in a wrongly designed system may lead to a malfunctioning of the RT system. A good RTOS can be defined as one that has a bounded (predictable) behavior under all system load scenarios (simultaneous interrupts and thread execution). In RT system, each individual deadline should be met. Real-time systems are designed to control and monitor their environment. Most of these systems are using sensors to collect environment state and use actuators to change something.