What is an Operating System ? Types, Purpose , Function and Services of an Operating System. | SchoolingAxis


operating system


An operating system handles the computer hardware and  Software resources of a system. An operating system works as a mediator between the user of a computer and computer hardware. The main objective of an operating system is to give an operational condition in which users can execute programs accurately and easily. 

What is an operating system? 

An operating system is possibly  considered as an  organized collection of software extensions of hardware, including control routines for operating a computer system. Other programs depend on  resources  allowed by the operating system to get access to system resources,  like file systems and input/ output devices. 

Programs generally invoke service at the operating system by means of operating-system calls.

An operating system is caring for the allocation of resources and services of a system,  Like  memory, devices, professors and information. An operating system additionally  involves programs to supervise these resources, like scheduler, traffic controller, memory management module , file system,  input/output devices. 

 Purpose of an operating system

  1. To provide an operating environment for a computer user to execute programs on computer hardware  accurately and easily. 
  2. To allocate the separate resources of the  computer system  as required to solve the given problem.
  3. Management of the execution of user programs to avoid any kind of errors and inappropriate use of the computer and similarly,  management of the operation and control of input/output  (I/O) devices . 

Functions of an operating system

The Operating  System as an Extended Machine- The function of the operating system is to give  users  the equivalent of  a virtual machine (extended machine)  that is uncomplicated to use or program than the underlying (basic) hardware. 

The Operating System as a Resource Manager- we all know that an operating system manages all the resources of a computer system internally. Like managing  memory,  files, Processor and input/output (I/O) devices. 

An operating system maintains the status of each resource, and decides who gets a resource,  for how long, and when. 

  Types of Operating System

There are various types of Operating system are-

Desktop System - Personal computers were introduced in the 1970s. Throughout the time of in their first decade, the CPUs (central processing unit) in PCs felt the need of Features required to protect an operating system from used programs. Hence, personal computer's Operating systems were neither multitasking nor Multiuser. The objective of these Operating systems has been replaced with time, instead of maximizing CPU and peripheral utilization, the systems choose for maximizing user comfort and responsiveness. 

These systems include PCs running Microsoft Windows  and Apple Macintosh. The Apple Macintosh OS has been ported to more modern hardware, and includes new features ,  like virtual machines and multitasking. Linux,  Unix like, the operating system that is available for PCs, has become well liked by users. 

Multiprocessor Systems - Multiprocessor Systems generally known as parallel systems. Multiprocessor or multiprocessing Operating system commands the operation of computer systems that include multiple processors. Multiprocessor Operating systems supporters concurrent execution of multiple tasks on different processors . It is also termed as a multitasking system.

Handheld Systems - Handheld systems are generally used for personal information managers. Such as phone numbers, names and so on. Many handheld systems  have memory between 512 KB and 8 MB. Due to restricted sizes of  such devices the developers of handheld systems and applications face many challenges . Another issue of concern to developers of handheld devices is the speed processors used in  the device. 

Clustered System - Cluster systems assemble multiple CPUs to accomplish computational work. But clustered systems are different from parallel systems , in parallel systems they are composed of two or more individual systems coupled together. The phrase clustered means the clustered computers share storage and are closely linked via local area network (LAN) networking. 

Real-time System - Real-time operating systems are used in a working environment where a large number of events, largely external to the computer system, must be received and processed in a short time or within certain deadlines. For example,  such applications are real-time simulations, industrial control and flight control.

The real-time operating system can be two types-

  1. Hard Real-time Operating System - critical tasks can be completed by this operating system within a certain range of time guaranteed. 
  2. Soft Real-time Operating System - Time relaxation provided  by this operating system. 

Multitasking - Multitasking operating system supports the execution of one or more active processes Concurrently. Generally multitasking is implemented to tackle the data of several processes in memory and  maintain code. Multitasking is coupled with hardware and software support for memory protection in order to stop  invalid processes from Corrupting address spaces and behavior of other residing processes. 

Multiprogramming - one user of a computer cannot keep either the CPU Or the input/output devices busy all the time. Multiprogramming improves the CPU utilization by organizing jobs so the CPU always has one to execute. 

Distributed System - In distributed operating System  Or loosely coupled system processors do not share memory, and each processor has its own local memory . Loosely coupled systems use only message passing for synchronization and inter processor communication.

Operating System Services

An operating system provides various kinds of services. These services are different from one operating system to another operating system. All these services are provided for the comfort of the programmer to make programming tasks easier. 

I/O Operation - A running program may need I/O , may involve a file or an I/O device. The main reason for Users cannot control I/O devices directly are efficiency and protection. Usually, the program that requires I/O, specifies only a function; the rest of the work is handled by the OS. 

Work as a Resource Allocator - when multiple users are using the system or multiple jobs are running at the same time. Then the resources are provided by the operating system such as some programs that want I/O devices and so on. 

File-System Manipulation - Each and every program needs to read and write files. It also needs to create and delete files by name. 

Error Detection - Errors may occur in CPU and memory hardware and in I/O devices and in the user program . So it's the responsibility of the operating system to constantly check the possible errors and also correct the errors for correct and efficient computing. 

Communication - This is another service provided by the operating system. When one process requires an exchange of information with another process. Then this type of communication can occur in two ways . The first one reason  takes place between processes that are executing on the same computer ;the other reason takes place between the processes that are executing on different computer networks  that are tied together by a computer network. 

Protection - This service ensures that all access to system resources is controlled. 


The basic knowledge of operating systems helps you to know the internal processing of a computer system. And also you are able to understand the working process of an operating system. 

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