Operating Systems

Why created  an Operating systems for computers?
As computer systems diversified and became more complex and powerful, it became increasingly impractical to write programs that functioned as both an operating system and a useful application.In response, individual mainframe computer owners began to develop system software that made it easier to write and run programs and operating systems were born. Every program that ran on these early systems had to include all of the code necessary to run the computer, communicate with connected hardware, and perform the computation the program was actually intended to perform.

History of operating systems.
The first operating system was created by General Motors in 1956 to run a IBM mainframe computer. And then In 1960 s, IBM was the first computer manufacturer to take on the task of operating system development and began distributing operating systems with their computers.GE, Digital Equipment Corporation are some of the companies who released mainframe operating systems in the 1960 s. Unix operating system was developed in late 1960 s. It was written in C, and freely available.
Windows operating systems were created for the request to run its range of personal computers. The first OS was built by Microsoft was called MS-DOS in 1981.There are three main types of operating systems. Those are Microsoft windows, Mac OS X and Linux.



What is an operating system?
Software that manages computer hardware and software resources and provides common services for computer programs.

Major Components of an operating system
1.Kernel
Consists of various modules and it directly interacts with the underlying hardware.

2.System Libraries
The special functions or programs using which application program or system utilities accesses kernel's features.

3.System Utility
programs that are responsible to do specialized, individual level tasks.

4.Process Manager
Decides how to allocate the CPU and keep track of state of each process

5.Memory Manager
In charge of main memory such as check the validity of each request
for memory space etc

6.Device Manager
Monitors every device, channel and control unit.



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