Real Time System
Real time system is an example of a general purpose operating system. This system is used when the requirements are inelastic for data flow or operations of processors so, it is often used as a control device in dedicated applications. Sensors are used to bring the data in computer. Computer analyze the data and possibly regulate controls for the modification of seniors input. some system that control the specific experiments, industrial control system, medical imaging system and some display systems are different forms of real time system. It also contains some systems like automobile engines fuel injection systems, weapon systems and home appliances controller. In real time system there is fixed time constraints. Processing is required to be done within defined constraints otherwise the system will fail.
The functionality of the real time system is considered to be correct only if it returns the correct results with in an any time constraints. Compare this requirement to the time sharing system where it is desirable not compulsory to response quickly, in batch system where there may be no time constraints at all. Time sharing system has two essences. A hard real time system there is guarantee that the critical task complete on time. According to this goal requirement all the delays in the system be restricted, from the retrieval of stored data to the time that it takes the operating system to complete any request made of it. These time constraints dictate the facilities that are offered in hard real time systems. Usually the secondary storage of any type is limited or missing, with data instead being stored in short term memory or in ROM.
ROM is situated on nonvolatile storage devices that retain their contents even in case of electric outage. Most of the advanced features are absent later they tends to separate the user further from the hardware that separate the results in ambiguity about the amount of time operation will take. That’s why the hard real time systems oppose with operation of time sharing systems. Another type of real time system is soft real time system where the complex real time tasks acquires the priority over the other task and retains the priority until it completes. In case of hard bounded system kernel delay must be bounded, on the other hand the soft real time system has more limited functions than a hard real time system.