Structure of operating system

Operating system performs three functions:
*Convenience: An OS makes a computer more convenient to use.
*Efficiency: An OS allows the computer system resources to be used in an efficient manner.
*Ability to evolve: An OS should be constructed in such a way as to permit an efective development, testing and introduction of new system functions without at the same time interfering with service.

Every operating system has its own internal structure in terms of file arrangement, memory management, storage management, etc, and the entire performance of the system depends on its structure.

The elementary approach to structure an operating system is simple structure. Simple structure OS systems are small, simple and limited systems. MS-DOS is an operating system designed with this approach.

Structure of MS-DOS

An operating system may process its workload serially or concurrently. That is resources of the computer system nay be dedicated to a single program until its completion, or they may be dynamically reassigned among a collection of active programs in different stages of execution.

The main element of an OS that a user sees is the graphical user interface or GUI. This is the display and the method of interaction that the user can take to manipulate the OS via the display.

For example, in a personal computer OS such as Windows 7, the user can see a desktop, a background and icons. These are manipulated by way of the keyboard and mouse usually. In a mobile computer OS such as Android, the user can see a main screen with icons that can be manipulated with his fingers, with stylus or by voice.
Structure of operating system