What is an operating system?

Answer 1

An operating system can be defined as a global application that acts as an intermediary between a computer user and the computer hardware. It manages the hardware and software resources of a computer. It allows the computers to run programs. An operating system allows the computer to start and function. It allows you to navigate your computer. It allows all the components of a computer to operate together to do tasks such as printing text to a printer. A word processor application sends its print request to the Operating System and the operating system carries out that task. A computer would likely be unusable without an operating system, unless the software is able to act as its own OS.

The goals of Operating system is to execute user programs and make solving users problems easier, to provide a convenient environment for the development and execution of programs, and to schedule computational activities to insure good performance of the computing system. Some operating systems are more user friendly than others. Ideally, the system should include easy to use icons, and easy to use pop-up instructions as needed. It can either be a graphical user interface (such as Windows, Mac, OSX) or a command line (Linux/Unix/DOS). It is the background in which all other applications and services run.

An operating system has two primary functions. Firstly, it dictates to application programs what they can and cannot do. Secondly, it manages the computer hardware on behalf of applications. The two functions are not unrelated.

It also manages execution of user programs to prevent errors and improper use of computer and operations and controls of I/O devices. If you had two applications, A and B running on the same computer, and no operating system to supervise them, then program A could overwrite the memory occupied by program B, or vice versa, program A could overwrite program B's files on disk. You could have the two programs trying to read from the same keyboard, or print on the same printer, simultaneously, and so on.

Additionally, if there was no operating system to manage the hardware, then applications would need to concern themselves with the minutiae of how to save data to disk by programming the hard disk controller, or obtain input from the keyboard by interrogating the keyboard controller, instead of getting on with the calculation of somebody's payroll, or whatever else that application was supposed to do. Computers with no operating systems relies on the application programs to manage minimal hardware. For instance, application programs would need I/O support libraries.