FUNCTION OF OPERATING SYSTEM

Usually Operating system is there to manage all pieces of a complex system
Imagine what will happen if three programs running on a computer all try to print their output simultaneously on the same printer. The first few lines might be from program one and the next few lines might be from program two and so on with the result resulting in chaos. The operating system can bring order to potential chaos by buffering all the output destined for the printer on the disk.


The primary task of operating system is to keep track of who is using which resource, to grant resource request, to account for usage, and to meditate conflicting request from different programs and users.


When a computer has multiple users, the need for managing and protecting the memory, input/output devices and other resources are even more apparent. This need arises because it is usually necessary to share expensive resource such as tapes drives and phototypesetters.


Operating systems perform basic tasks, 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.


For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different program and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.


The set of software products that jointly controls the system resource using these resources on a computer system is known as operating system.


Examples are Unix, Windows.