Introduction Of Operating System History, Role, Types

Introduction Of Operating System

Introduction Of Operating System

Introduction Of Operating System

The Computer system is the collection of input unit, output unit and processing unit with software. Large Numbers of programming languages are used to write a program. The computer not only uses high level language, but also uses low level and machine level  language.

It consists of a large number of devices such as hard disk, microprocessor, monitor, keyboard, etc. The  Operating system is the powerful program that controls all things that mention above. The operating system is a result of many years’ devotion of scientists working on different models of computer systems.

The types of operating systems are changed due to changing working environments and needs of users.

History of OS

  • First generation (1950). The digital computer is invented in 1940, but it works without any operating systems. In 1950, the first operating system is designed and implemented in IBM 70 by General Motor Research. It is very primitive and single stream batch processing system.


  • Second generation (early 1960). The shared system with multiprogramming real time systems concepts are applied in this generation. The real timing system is used to control chemical processing in industries, and military weaponry systems.


  • Fourth generation (mid 1970 to present). The design of LSI(large Scale Integration) had
    Major role in development o1’advance level operating system. This OS of this generation is very efficient due to many fantastic changes to control memory, files, input output devices and other peripherals. The PC (Personal Computer) becomes available for all due to the microprocessor and the OS is dramatically spread over the market. The MS-DOS and UNIX operating system were most dominant OS in the beginning of fourth deterioration. MS DOS is coded by Microsoft for Intel B0BB CPU, and UNIX for Motorola 6899 CPU. The user friendly OS with many program icons, tray, menu, prompts are available in the market. The OS with voice reorganization capacity is also available.

Organization Of OS

The operating system is an interpreter between user and computer. It is like a main gate to enter into the computer system. It provides an environment to interact with other software and perform several types of management and controlling functions” It runs all the times and provides a platform for application software. The primary purpose of an operating system is to maximize the productivity of a computer system by operating in the most efficient manner. An operating system minimizes the amount of human intervention required during processing.

The operating system runs all the time, and provides a software platform on top of which other programs, called application programs, can run. It is responsible for bridging the gap between the hardware and application needs. It manages the hardware and supplies ‘service’ to the application program. Example: Its services include file management, memory management, processor management, process communication, and networking.


UNIX, Linux, Mach, MS-DOS, MS-Windows, Windows/NT, Chicago, OS/2, MacOS, VMS, Vlrl, etc.

Role Of OS

An Operatittg system is defined as a set of system programs that control and                      coordinate the I overall operations of a computer system. It also acts as an interface          between hardware and user.


An operating system manages and coordinates the functions performed by the computer hardware, including the CPU, input/output devices, secondary storage devices, and communication and network equipment, An operating system is the program that we see when a computer is turned on  and again see when a computer is turned off.

Each general purpose computer must have OS to run other programs. An operating system performs basic tasks, such as recognizing input from the keyboard, sending output to the screen, keeping track of files and directories on the disk, and controlling peripheral devices.

It is system software that keeps track of each hardware resource, determine who gets what, determine, when the user will have access to the resource, allocate how much of the resource the user will be given, and terminate access at the end of the user period.

The primary purpose of an OS is to maximize the productivity of a computer system by operating it in the most efficient manner and minimizing the amount of human intervention required. An operating system also simplifies the job of computer programmers. Some of the facilities provided by modern operating system are summarised below.

1. Easy interaction between humans and computers, also known as human computer interface.
2. Starting computer operation automatically when power is turned on.
3. Loading and scheduling users’ programs along with necessary computers.
4. Controlling input and output.
5. Scheduling processes.
6. Managing various types of memories such as primary, secondary cache sets.
7. Managing and manipulating files i.e. Opening, writing, editing, and closing.
8. Providing security to users’ jobs and files.
9. Identifying, handling, and recovering files after a failure.
10. Accounting hardware resources and handling network communication.
11. Allowing users to share data and software among themselves’
12. Preventing the system form unauthorized uses, computer viruses etc.
13. Translating programs from one form into another form.

Types of Operating Systems OS

There are many types of Operating systems. Which are given below: 

OS are divided into different types depends on their properties. Mainly are single user, multi-user, multiprocessing, multiprogramming, multithreading, real-time, distributed.

  1. Single User
  2. Multi-User System
  3. Multiprogramming
  4. Multitasking
  5. Realtime System

Single User

It supports only one program at a time. The MS-DOS, PC-DOS, etc. Are single user OS.

Multi-User System

When are more than one operator is processing data at a same time using one CPU is called Multi-user or Time- Sharing System. In this system, each operator has a time slice to accomplish his or her process using the processor.

Time Slice: Srnali time allotted by the operating system to each operator for utilization of processor is called time-slice. Its value is very small, so each operator feels that the processor is processing his or her job only. In film story, we see a fraud lover allots times to with his two or girl friends and each girl friend feels that her lover is devoted in her love, Just like it, each operator feels that the processor is processing only his or her job.

Turn around time: It is a time between submitting a job and receiving the output.




The process of maximum utilization of CPU keeps it busy is called N4uitiprogramntirrg or
Concurrent Programming. In this environment, processor processes several programs simultaneously.


A System able to process a number of tasks at a tim0 is called Multi-tasking within a well defined fixed time constrain is called Real- Time System.

Realtime System

The Rteal-time systems are used in every field of life. The very common example of real-time control is muitimedia and virtual reality.

Full Form Of OS

Full form of OS : Operating Systems