Real-time systems are computer systems that monitor, respond to or control an external environment. This environment is connected to the computer system through sensors, actuators and other input and output interfaces. It may consist of physical or biological objects of any shape and structure. Often humans are part of the connected outside world, but a wide range of other natural and man-made objects, as well as animals, are also possible. The computer system must comply with several timings and other restrictions imposed by the real-time behavior of the external world to which it is interconnected. Hence the name comes in real time. Another name for many of these systems are reactive systems, because their main purpose is to respond or react to signals from their environment. A real-time computer system may be a component of a larger system in which it is embedded; Reasonably, said computer component is called an embedded system.
Applications and examples of real-time systems are ubiquitous and proliferate, appearing as part of our commercial, governmental, military, medical, educational and cultural infrastructures. Are included:-
O Vehicle systems for cars, subways, airplanes, railways and ships
O traffic control for roads, airspace, railways and sea lanes
Or process control for power plants, chemical plants and consumer products such as soft drinks and beer
O medical systems for radiotherapy, patient monitoring and defibrillation
Or military uses such as firing weapons, tracking, and command and control
O systems of manufacture with robots
O communications by telephone, radio and satellite
Computer games
Or multimedia systems that provide text, graphics, audio and video interfaces
O home systems to monitor and control appliances
O building managers who control entities such as heat, lights, doors and elevators