Introduction to Operating system structure

In this post we will first discuss the introduction to Operating System structure, After which we will discuss the functionalities of the operating system.

What is an Operating System

An Operating System is a system software, Which means it is a software which is inside your computer system or we can say it acts as an interface between hardware and software of the system.

It works as an interface between the user and the hardware. This is the definition of Operating System in a simplest language.

 Or we can say with a handful of users at the front end, the interaction between the users and the hardware is established by the Operating System of the computer.

operating system
Operating System


Part of the computer which can be seen is called hardware like monitor, mouse, CPU etc. Let's consider the scenario of our own laptop or desktop, Basically hardware is nothing but the CPU Which we call 'the Brain of the system' after which comes the Input/Output Devices.

Input/Output Devices

Devices through which we give input or take output of the system called input/output devices like Keyboard, mouse, printer, scanner etc. are my input/output devices.

operating system structure
Operating System Structure

Random Access Memory(RAM)

Random access memory(RAM),we call generally as Main Memory Other than that secondary memory like our hard disk.

As its manes suggests it can be accessed randomly. RAM is a volatile memory.
So this is the hardware we have in a system. When we access these hardware then I am accessing these devices only.

But am I accessing these devices directly? Are users directly accessing the devices, that is, the hardware? No, they are accessing them through the Operating System, So the operating system works here as an interface

Need of Operating System

The next point is, why is there a need for an Operating System? Without operating system we have to write program every time when we need to access some applications.

So operating system make it easier to access the computer or any devices and make also user friendly so that a man without knowledge of programming skill can access the our system.

 So let's assume we want to execute a print command, Let's say we have a word file and we want to print that file.
 But I can't directly go to print option and print the file, I will have to first write a program to invoke the printer so that the printer will print the file.

CPU(Central Processing Unit)

Its stands for central processing unit. It is also called brain of our system and it decide what to do and what to do don’t.

 If we talk about the CPU If there's a process, if I wish to execute a job, The execution of the job comes later. The first task would be to provide the CPU with an instruction.

How will we provide the CPU with that instruction? We will have to write programs exclusively for that Due to this reason, the interaction (communication) between the user and the hardware would turn way too complex.

There could be another scenario in which, a user has accessed one particular device. When another user wants to access the same device, I don't release the resource Why so?

It is because I have directly accessed the hardware .So there is no authority in between who can take back the access from me So, there are several such reasons due to which we have to use an operating system Which serves as an interface between the user and the hardware.

We will see those when we discuss the functions Every single function of the operating system can be considered as the reason for using an operating system in our system (computer).

 So if I provide a basic example to the operating system The operating system used majorly is Windows If we talk about the primary function of the Operating System or why we use an operating system.

 The major goal of the operating system is to provide convenience To provide convenience to the user Yes. To provide convenience, in the sense, to make it easy for the user to access the hardware That's the functionality of the Operating System.

Throughput of Operating System

It is the number of tasks executed per unit time. That's the simple definition of throughput.
 So as the number of tasks executed in a particular amount of time keeps increasing, my throughput increases too.

So we require an operating system that has a high throughput as well as is highly convenient.

 But at present, the market acquisition of Windows as of 2018 is at approximately 82% Means, the acquisition of the market right now has severely dropped as compared to the last few years The market acquisition of Linux which was at 1 or 2 % earlier has gone up Why?

Because of its throughput Other than this, we also have other operating systems like Apple's own Operating system which is called Macintosh that has a good user base too.

So if we look into the real-life examples of operating systems, we have Windows, Linux, Mac and many more, But the major goals narrow down to convenience and throughput.

Basic function of the operating system

The major functionality of the operating system is, it acts as a resource governor or a resource manager It manages the resources.

If I am the only user of my system, I do not require the resource governor, But wherever there's parallel access, that is, when multiple users access the system or particular hardware Which usually happens at the server level. If we talk about the server where a lot of users send requests to access the data. There the operating system serves the role of a resource manager.

The user who gets the access, the amount of time the user gets access to the device and such are decided by the operating system.

 After the stipulated time, the operating system revokes the access of the device from the user.
 That's how we manage the resources, so that, the load doesn't build over a particular device.
When we open the task manager in our system. We could easily find a lot of values in wave-like representations.

task manager in operating system
Task Manager in Operating System

 Which denote how much of CPU resources we are using, how much of RAM we are currently using, etc. All those values are managed by the operating system.

So that the load over the system neither exceeds the optimum usage limit nor falls way too below Means, it tries to manage the resources at the optimum level.

Storage Management in Operating System

The second point is Storage Management Or we can say next comes Process Management. Process Management means In our systems, we manage the processes Means, we execute the processes.

 I turn on my laptop and start working on Microsoft Word Along with that, I open Windows Media Player and also a gaming app Means, I open multiple processes simultaneously.
 All these processes are executed by the operating system How does this work?

 The mechanism is called CPU scheduling. We use various CPU scheduling algorithms.
 Let's consider that I have written a simple C Program and saved it in .c format. Now I have to execute the program and the program gets converted into a process.

 Now the process gets executed in the CPU. The execution of the process in the CPU is taken care of by the CPU scheduling mechanism.

 CPU scheduling consists of several different types of algorithms which help to access the CPU and execute the processes efficiently.

 This management is taken care of by the operating system.Other than this comes the Storage Management. Storage Management involves storing data in the secondary storage devices which includes the Hard Disk
 Which actually means the data which we want to store permanently, The way in which it is stored is managed by the Operating System And how do we manage the storage?

File system in Operating System

By file system NIFS and CFS, I mean CIFS and NFS Common Interface File System and Networked File System.

 These two are commonly used in Linux and Windows. Their major goal is to handle all data input to be stored permanently inside.

The Hard disk with the help of the File System Inside the tracks or sectors whichever is applicable as a Disk Architecture Which in turn is managed by the Operating System.

Memory Management in Operating System

The Fourth One is Memory Management. In Memory Management there is RAM. Because If we differentiate between Storage and Memory Management, Storage Management involves Hard Disk It is the functionality of the Operating System to manage the Hard Disk efficiently.

 But hard disk has no constraints whereas RAM has a constraint which is Limitation of Size. In the sense the RAM, to which all the processes that are ready for execution are stored, is limited.

 This topic is called as multitasking or multiprogramming concept in which the processes to be executed are brought in to the Main memory or RAM and when they arrive inside the RAM, they are made to wait in a queue inside the CPU.

 So how much memory we need to utilise to execute the process and how we can take the memory back is what we call as allocation and de-allocation of memory.

 Just because RAM has limited storage, we cannot simply let an already executed process as it is in RAM without giving space for the next process to enter.

At that time the Operating System sends the executed process out of CPU and lets a new process in which is termed as Swapping.

As I have told that a process under execution gets an allocated memory inside the RAM for the process to be stored, Like for P1, the memory segment is 0 to 100. Another process P2 has got 101 to 200 memory segment.

 When any process calls or executes an instruction outside its segment or block, then the process on the whole gets totally blocked. Means if the process P2 calls or executes any instructions from that of P1 block, then P2 gets completely blocked.

Means the privacy and security is maintained even among the processes. so that they don't interfere or interchange data with each other. So privacy and security is also given by Operating System.

The last point that is note the diagram where the concept behind the term Applications is How we as normal users try to access the Operating System?

When we switch on a computer the Desktop acts as an interface to the user with Operating System.  We go to My Computer where if we want to watch a movie or listen to songs we open C, D or E drives and access the particular file

Now the user can access the files through the applications or through direct access to Operating System. Majorly we use applications only if, for example, if I want to take a printout of a particular file, then what will I do? First I will make it a MS Office file which is an application. Now if I press Ctrl+P a dialog box pops up asking "Do You Want To Print?" and we would give "Yes" giving it the print command. Here the print command is providing us access to hardware.

But you are directly accessing the hardware through an application for which the Operating System acts as an interface.

 Do you as a user feel it? Not at all It doesn't give us that feel so it gives a good interface that the user is not at all felt the presence of Operating System during accessing the hardware.

So we have learnt about basic introduction of operating system, operating system structure,function of operating system and memory management by operating system.


What is an Operating system short answer ?

Operating system is an computer program which manages hardware of the system and act as an interface between hardware and software of the system.

What are the types of operating system ?

There are different type of operating system based on its utility..
  • Real time operating system
  • Network operating system
  • Time sharing operating system
  • Batch operating system
  • Distributed operating system
What are the example of Operating system ?
  • Window of Microsoft for PC
  • Google's Android for mobile
  • Apple's IOS
Who is the father of OS(Operating System) ?

Father of OS(operating system) is Gary Kildall an American scientist. 

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