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8. Real Time Operating System

A real-time operating system is found in systems which aim to control a series of actions by using a computer.

For example the engine management computer under the bonnet of the modern car has micro-second control of the engine and exhaust system. It has dozens of rapidly changing inputs such as throttle position, brake pedal position, engine speed and so on.

It needs to take all of these inputs, then process them to produce a set of outputs that control the car.

Note that 'Real Time' does not always mean 'fast'. For example, a traffic light computer has a real time operating system that only needs to react within seconds (but react it must!). On the other hand, a safety critical embedded computer as you might find in a braking system would need to react in microseconds.