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In this article:
- What is an Operating System
- Functions of an Operating System
What is an Operating System
An Operating System or an OS is a software program that has the responsibility to mange the software and hardware resources of a computer system. The Operating System controls and allocates memory to programs, processes and manages instructions, controls and interfaces with all input and output devices, facilitates network operation and maintains and manages the files.
Computers today run various software applications that serve one purpose or another. These software applications are commonly called Application Software and they specialize in fulfilling a particular need of the user. However, this also makes them limited in the sense that they can only ‘ask’ for resources to run from the system they are on but cannot manage them themselves. This is where an Operating System comes in handy. The Operating System accepts all the requests from such application software and allocated them the required resources one by one. In this way, an Operating Software allows many software applications to run at the same time and at the same time makes applicaion software programming easier by taking the responsibility of resource allocation.
Functions of an Operating System
An Operating System performs certain important functions. These are critical to the proper working of a computer system and have been discussed below:
- Process management
All software on a system runs inside what is called a process. It is a known fact that computer resources are limited. This means that at a time, only one process can run on a computer. However, this would limit a user and make him narrow down his work so as to work on one thing at a time. Modern operating systems need to deal with this problem. They enable the user to run more than one process at a time within the same limited resources. This is called multi-tasking and the technique used by an OS to achieve this is called time-sharing. Since a computer usually has only one processor, multi-processing is not possible. So, by using time-sharing, the OS allows each task to have the resources to itself for a certain period of time (often, in milliseconds). The OS does this in quick succession such that the user cannot feel a difference in speed (though it can be seen in systems that are too low in resources).
- Memory management
Software that runs on a system try to get as much memory as is availabvle for using. Given an infinite amount of memory, single software can gobble up all of it when it runs. To prevent this, the OS performs the important function of Memory Management whereby it allocates the memory to each process (that is, software). It also takes care that the memory is easily accessible and that once used, the memory is freed for further storage.
- Networking
Though the protocols in use today are platform independent, software applications cannot interact with them until there is an operating system acting as a mediator. For example, it is the Operating System that interfaces between the applications and the Internet (which usees the TCP/IP protocol). This way, operating systems facilitate networking and sharing of commonly used resources such as printers etc.
- User Interfaces
For an Operating System to be of some real use, it is important that it provides the user with an interface to interact with the computer system. This is probably the most important function of an OS. An OS, hence, acts as a mediator between the user and the computer system and its software. While traditionaly, user interfaces were text-based (called command line interfaces), many of the OSes today have a GUI, that is, a Graphical User Interface.
- Device drivers
A computer system is not capable of doing many functions at a time. For example, a computer cannot print on paper by itself. For this and such other functions, a computer uses peripherals. Peripherals are devices connected to the computer. These peripherals add functionality to the computer by interacting with it through an operating system. The operatin system, however, cannot in any way, recognize the plethora of peripherals. To deal with this situation, an OS makes use of a device driver which is a type of computer software used to interact with a particular type of hardware. Thus, device manufactureres don’t have to worry about the design of the computer system or the operating system. Rather, they only have to create a device driver program to help the operating system interact with their device. This is abstraction.
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