What is an Operating System?
An operating system; abbreviated as “OS”; is the software that, after being initially loaded into the computer by a boot program; manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources.
Operating system 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. It also provides a software platform on top of which other programs, called application programs.
An operating system performs these services for applications:
- In a multitasking operating system where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn.
- It manages the sharing of internal memory among multiple applications.
- It handles input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports.
- It sends messages to each application or interactive user (or to a system operator) about the status of operation and any errors that may have occurred.
- It can offload the management of what are called batch jobs (for example, printing) so that the initiating application is freed from this work.
- On computers that can provide parallel processing, an operating system can manage how to divide the program so that it runs on more than one processor at a time.
The most commonly-used contemporary desktop OS are Microsoft Windows, Linux, VMS, OS/400, AIX, and z/OS.