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Operating System And Its Functions

Operating System And Its Functions – Operating System Provides Interaction Between User And Hardware.


CPU – CPU Is Called As Brain Of The System.

I/O Devices  РKeyboard, Mouse, Printer, Scanner Etc Are Some Of The I/O Devices.

RAM – It Is Called As Main Memory.

Hard Disk – It Is Called As Secondary Memory.

  • User Accesses The Hardware Through Operating System.
  • Operating System Works As The Interface Between User And Hardware.

Why There Is A Need Of Operating System?

What Happens If There Is Not Operating System?

If There Is No Operating System And If User Wants To Access The Hardware. The User Need To Write Program To Access Hardware.

Through Programs User Accesses Hardware.

Repeatedly(Everytime) User Should Write Programs For Different Hardware Devices To Access Those Devices.


If User Wants To Print A Document, At That Time User Should Write A Program For Printer To Understand It And To Invoke The Printer To Give Print.

Like That For CPU, If User Wants To Execute A Job. User Should Write A Program, User Should Give Instruction To The CPU In The Form Of Program.

If User Writes Too Many Programs For Too Many Devices For Too Many Times. The Communication Between User And Hardware Becomes Very Complex(Very Tough).


If User 1 Is Accessing A Hardware Device, The User 2 Cannot Access The Same Device Until The User 1 Releases It.
Like That There Are Lot Of Reasons To Use Operating System.

The Functions Of Operating System Are The Reasons Why User Needs Operating System To Use Hardware.


Majority Of The People Uses Windows Operating System.

The Major Goal Or The Primary Goal Of The Operating System Is To Provide Convenience To The User.

This Is Why The Reason Windows Operating System For Many Years It Acquired In Market.

95% Of The Users Used Windows Operating System At Some Point Of Time.

Day By Day The Problems Solved By The Operating System Increasing Gradually.

User Wants To Solve His Problems Very Fastly.


Throughput РThroughput Means Number Of Tasks Executed Per Unit Time.

The Number Of Tasks Done By Operating System Are Increasing At A Particular Amount Of Time. The Through Put Also Increases.

So User Need A Operating System Which Has More Convenience And More Throughput.

Throughput Is Used Mostly In Linux Operating System.

But It Doesn’t Mean That Linux Operating System Is Not Providing Convenience.

Windows Acquired 95% In The Market Because Of Convenience.

In 2018 The Windows Operating System Usage World Wide Is 82%, The Acquisition Of Windows As Decreased As Compared To The Last Years.

Linux Acquisition Was 1% Before But Today It Increased Because Of Throughput.

Apple (Mac Os) Is Also Good Today In Market But That Is Different.

Major Goal Of OS Is Convenience And Throughput.


Functionalities Of Operating System

First Functionality And Major Functionality Of Operating System Is Resource Management

Example – If Multiple Users Are Accessing(Using) Resources(Hardware). Operating System Allocates Hardware Devices Based On The Requirement. It Takes Hardware From One User And Allocates To Another User. In Simple Words, The Operating System Manages The Resources (Hardware).

If User Opens ‘Task Manager’ In The System, User Can See How Much ‘CPU’ Is Used And How Much The RAM Is Used, All Those Values(Percentage Used) Managed By Operating System.

Process Should Not Take More CPU Or Less CPU, Operating System Loading Percentage.

Resources Are Used Properly With Operating System.

Specially In Parallel Processing. This Management Is Used Where Multiple Users Tries To Access One Device At The Same Time.


Process Management

Processes Are Managed By Operating System.

Processes Are Executed By Operating System.


User Using MS Word And At The Same Time User Uses Windows Media Player And Also User Using A Gaming App.

Which Means User Is Using Multiple Processes.

How All These Processes Should Be Executed. That Is Also Done By Operating System.

This Is Done Using CPU Scheduling. To Do This Various CPU Scheduling Algorithms Are Used.

CPU Scheduling Means To Execute A Process, User Writes A Simple C Program And That C Program Is Saved With .C(Extention)

Now The Program Have To Be Executed Means The ‘Program’ Becomes ‘Process’.

This Process Is Executed In ‘CPU’

So How To Execute That Process In CPU?

That Is Done By The CPU Scheduling.


There Are Different Types Of Scheduling Are Used. To Use CPU In Proper And Efficient Way, To Access CPU , To Execute Processes These Algorithms Are Used.

All These Are Donf By Operating System.

Storage Management

Harddisk Is The Secondary Storage Device, Which Stores Data Permanently.

How To Store The Data In Harddisk?

It Is Managed By Operating System, The Storage Of Data In Harddisk Is Managed By Operating System.

Storage Management Is Done Through ” File System

NIFS, CFS, NFS Are Used In Linux And Windows Operating System.

The Data Will Be Stored In Harddisk And File System Manages The Data Storage In Harddisk.

The Data Stored In Harddisk And File System Manages The Data Storage In Hard Disk And Data Stored In Harddisk Through Tracks & Various Sectors Based On The Architecture Of The Harddisk.

Memory Management

RAM Comes Under Memory Management.

RAM Has Limited Size Where Harddisk Has Huge Storage Space.

All The Processes Will Be Executed In RAM First.

This Is Called As Multi Tasking Or Multi-Programming.

All The Processes Will Be First Executed In RAM.

From RAM The Processes Will Be Sent To CPU One-by-One.

Operating System Allocates Certain Percentage Of Memory To The RAM Based On The Process And After Executing The Executed Value Will Be Taken And The Memory Size Gave To RAM Will Be Deallocated.

For Every Process, This Happens.

Allocation & Deallocation Of Memory, Managed By Operating System.

This Allocating & Deallocating Memory To RAM And Sending Process & Receiving Executed Value From The RAM Called As Swapping.


Security & Privacy Is Also Provided By Operating System.

When User Switches On The System, The System Asks The ‘Password’

Only The User Who Has Password Can Only Use The System.

Windows Uses Carbo Security Protocol And Saves That Password In Files And It Will Not Allot Unauthorized Users To Access System.

Operating System Provides Security In Between The Processes In RAM.

One Process In RAM Cannot Access Another Process Without Permission.

Data Exchange Will Not Be Done And One Process Cannot Interfere With Another Process.

Security And Privacy Is Also Provided By The Operating System.


Resource Management, Process Management(CPU Scheduling), Storage Management(Harddisk)- File System, Memory Management(RAM) Are Few Functionalities Of Operating System, There Are Many More Functionalities Are There.



When You Switch On The System, Desktop Is The Interface With Which User Interact.

User Opens My Computer, C D E F Drives And Opens Audio, Video, Document Files.

User Can Access Files Only Through Application?


User Can Directly Access The Operating System?

Majority Of Users Accesses Operating System Through Applications.


If User Wants To Give Print File(Document)

User Creates Document In MS Office(Application)

From That Application, User Clicks “Ctrl+P” For Print.

The Command From Application To Access The Hardware(Printer).

Operating System In Between Application & Hardware Is Working Like Interface.

User Cannot Feel That.

This Is Very Good Creation.

User Don’t Know When He Is Accessing The OS And When He Is Not Accessing The Hardware.


Another way (SHELL)

User Can Access Operating System Directly By Going Into Command Prompt(Cmd Pmpt) And Can Access Kernel.

In Linux, User Opens Terminal To Access Operating System And User Enters Different Commands In It Like ( Print, Read, Write, Open Etc)

Operating System Works With System Call.

Any Command Given Through Application That Invokes System Call In OS.



When User Open A File In My Computer->D-Drive, User Double Clicks On The File And File Opens.

Operating System Is Opening That File Through Open System Call

There Are Alot Of System Calls Through Operating System Works Between User, Application & Hardware.



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