Operating system

Operating system is the interface between computer and application software packages . Without OS no computer can be operated. For a computer system, it is regarded as the heart of living being . In other world ,the OS is defined as a program or suite of programs that control the entire operation of the computer, such as recognizing input from the keyboard , sending output to the display screen ,keeping track of files and directories on the disk , and controlling peripheral devices such as disk drives and printers etc . The routines , which performed input and output were especially important .Each input and output device had its own characteristics requiring careful programming .A special program routine was written for each input/output (I/O) device.