A real time operating system is an operating system that assurance a positive facility inside a particular time limits. Certain real time operating systems are produced for a exclusive application and also for other common purpose. Real time operating systems are frequently essential in small embedded operating systems that are packaged as part of micro devices. A Real Time Operating System has to be multi-threaded and detectable. Mainly the real time operating systems use layers of functionality planned to reduce real time development.

The real time operating systems are necessitating for multitasking, Process threads that can be prioritized and an enough number of interrupt levels. These layers add computational transparency and can overcome the natural determinism. Real time operating system set of modular components offer major cost savings as well as an easy way for reducing the amount of ROM and RAM necessary to run in our system.