Page 66 - Computer - 10(A&B)

1 1 3 3 Information and Communication
Digital Documentation
Technology Skills-II

Session 1

Operating System

A computer is a wonderful machine that enables us to do a number of tasks easily and
quickly. A computer system is a combination of hardware and software. The hardware,
that includes all tangible parts of the computer system, are devices. Software comprises
of programs that contain instructions to run these devices and let us do our work. But
how is it all coordinated? What makes the hardware and software programs work
together seamlessly and without any problems? The answer is the Operating system.
Software are of different types – system software, application software, and utility
software. Of these, the system software, also called the Operating system, is the most
important one.

Operating System
An Operating System (OS) is an interface between a computer user and computer hardware. It is the software
which performs all the basic tasks like file management, memory management, process management, handling
input and output, and controlling peripheral devices such as disk drives and printers.
The operating system is the first software installed in a computer. A computer is useless without an operating
system.

Need for Operating System
A user has to interact with the computer system to get its work done. But the computer is unable to understand
the language used by computer users as it understands only machine language. The machine language is in
Binary code, consisting of streams of Binary digits – 0 and 1.

The operating system works as a language interpreter between the user and the hardware so that the two can
interact with each other. But this is not the only need for an operating system. The computer system needs
programs to manage its various resources such as the processor, memory, the data stored on the hard disks
in form of files, and manage the overall functioning of the computer. The operating system handles all these
functions in the computer.

Functions of an Operating System
The operating system is the first program that is executed as soon as the computer is switched ON and continues
to execute till the computer is switched OFF. The various functions carried out by the operating system are:

Memory Management
Memory management refers to management of primary memory, also called RAM (Random Access Mrmory).
Main memory provides a fast storage that can be accessed directly by the CPU. For a program to be executed,
it must be in the main memory. An operating System keeps tracks of primary memory, i.e., what part of it are
in use by whom, what part is not in use. It decides which process will get memory when and how much. The
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