all of sani

From the computer's point of view, the operating system is the programm that is most intimate with the hardware. We can view an operating system as a resource allocator. A computer system has many resources- hardware and software- that may be required to solve a problem: CPU time, memory space, file-storage space, I/O devices, and so on, The operating system acts as the manager of these resources. Facing numerous and possibly conflicting requests for resources, the operating system must decide how to allcate them to specific programs and users so that it can operate the computer system efficienty and fairly.
A slightly diffirent view of an operating system emphasizes the need to control the various I/O devices and user programs. An operating system is a control program. A control program manages the execution of user programs to prevent errors and improper use of the control of I/O devices.
In genral, however we have no completly adqueate defination of an operating system. Operating systems exists because they are a resonable way to solve the problem of creating a useable computing system. The fundamental goal of computer systems is to execute user programs and to make solving user problems easier. Toward this goal, computer hardware is constructed. Since bare hardware alone is not particularly easy to use, application programs are developed. These programs require certain common operation, such as those controlling the I/O devices. The common functions of controlling and allocating resources are then brought together into one piece of software: the operating system.