Summary

	The operating system has been developed to ensure good performance of the computing system.
	It provides a convenient environment for the execution of programs.
	The history of the operating system development is described from the early developed operating system to
	to the modern operating systems.
	The modern operating systems include multiprogramming, time-sharing and real-time operating systems.
	The main components of the computer systems are described.
	The different registers in CPU are described and an example of instructions execution is given.
	Finally, the different management functions of the operating system are briefly described which will
	be explained in the next following topics.