Introduction to Operating System

Hello everyone and welcome to the first lecture in the course Operating System. So, Operating System is a course that is very important as far as computer science is concerned. And also, electronic students, you may have this subject in your course. So, it is equally important. And this subject, it consists mainly of theory as well as problems. So, we will first see the theory and also we will be solving the problems related to this subject. And we will see what this subject means. and what we can learn from this subject. So, first of all, this is just an introduction to operating system. And we will see what this operating system actually means and what are the functions of this operating system. What are the types of operating systems that we have? And we will just try to get a brief idea of this subject. Alright, so let's get started. So, here it says that an operating system also abbreviated as OS is a program that manages the computer hardware. and it also says it also provides a basis for application programs and acts as an intermediary between computer user and computer hardware. So, before we understand these two lines, I will be explaining it to you with a diagram. So, before we go into this diagram, here are some examples of some operating systems that we widely use these days. First is your Windows. So, you may be using Windows in your desktop or your laptops. So it is one of the famous operating systems used by many people. And also we have Linux and Ubuntu which are also two open source operating systems that are widely used in your desktops, laptops and other devices. And then we have the Mac OS which is the operating system from Apple. So in their laptops or in their MacBooks they use the Mac OS X and then in the iPhones we find iOS operating systems. And then we have the very famous Android which you must be having in your phones. So, Android is one of the famous operating system that is used for your mobile devices. Alright, so now before we try to understand these two lines that we have written here, let us take a diagram to understand the basic structure of a computer system so that we can understand what is an operating system and what does an operating system actually do. So, here I have a diagram which represents the basic structure. or the basic components of a computer system. So, first of all in the lowermost level, we have the computer hardware. And what are computer hardware? Computer hardware, it consists of resources like CPU, which is a central processing unit, and then memory, and then the I.O. devices, which means input-output devices. So, your resources like the processing units, your CPU, and also your memory. Memory consists of primary memory, like your RAMs and your secondary memory like your ROMs. So, these things also I will be explaining it in a detailed way in another lecture. So, let's first know that our memory as well as the I O devices. I O devices means the input output devices. These are the devices that you use for either giving input to your system or for getting output out of your system. So, examples of input devices will include your devices like your keyboards, mouse, your microphones these are devices that you use for giving input into the system and then output devices would be that devices that you use for getting output out of your systems that would be your devices like monitors or speakers which gives you output or which shows you or makes you hear the output those are your output devices so all these things they fall under computer hardware so we generally refer them to as resources all right And then on top of this we have the operating system. But for now let us just forget this operating system for a while. Let us just assume that it is not there. And then on top of this operating system we have the system or the application programs. Now there are two kinds of software we have which is system software and application software. And system software are the software that are used to directly modify or directly give some command to the computer hardware. And operating system is also a kind of system software but let's not think about that and let's not get confused hearing that but let's mainly try to understand what are application programs. Application programs are the programs or softwares that are used to perform a specific task and that can be directly used by the user. And these are some examples that we have here. First is a word processor. Word processors are like your Microsoft Office Word which are softwares used for making Document files, I believe that we have all used Microsoft Word. And then we have spreadsheets. Spreadsheets are like your Microsoft Excel. Okay, that is used for making tabular data or for making some calculations in your tabular data. And then we have compilers. So, if you are a computer science student, you may be knowing what compilers are. So, compilers are the software that we use for writing our computer. Codes like C++, C or Java are written into your compilers. And then we have the text editors. Text editors are editors used for modifying or writing text like your notepad, wordpad etc. And then we have web browsers. Web browsers are the softwares that enable you to browse the web. Even as you are watching this video in YouTube, you may be using some web browser to view this. And examples of this are Google Chrome, Mozilla Firefox, Internet Explorer and so on. So, this is not the only application program that we have. We have many many application programs. And these are just few examples I took to make you understand. So, these are the application programs we have. And on top of that we have the users. That is like users like you and me who are trying to use these softwares for performing specific task. So, let us take a simple example that this user 1 He wants to use the word processor. Let's say it is Microsoft Office Word. So, he wants to use word for typing some documents and he wants to save it to his system. So, let's see how he does it. So, we imagine that there is no operating system over here. We just have this user and the application programs and then the computer hardware. So, if he wants to write a document or if he wants to type something into Microsoft Word, then he has to type something into Microsoft Word. tell the computer hardware that he wants to do it. Now how can he do it? Since there is no operating system, he has to explicitly tell the computer hardware what he wants to do in the form of code. So, he has to first open the Microsoft Word and he has to tell the computer hardware that I want to load Microsoft Word. So, please load it into the main memory. And then after it is loaded, he has to type something. And when he types something, whatever he types, It has to be displayed on the monitor. He has to tell the computer hardware to do even that. He has to tell, please display the things that I am typing on the computer screen or on the monitor. And then after doing all that, he has to save it. And even for saving it, you have to tell the computer hardware that yeah, I am done with all my typing. And now please save this file with a particular file name to my hard disk. So, for each and every small or minute task you have to perform, you have to explicitly tell the computer hardware what to do and how do you communicate to it in the form of codes. You have to write source code, you have to write codes for each and everything that you have to perform. So we see that it is a very tedious task or it is a very difficult task to do this if there is no operating system. You have to manually tell the computer hardware each and everything that you have to do. So if it was like this then nobody would actually use a computer system or At least common people would not use the computer system because it is such a tedious thing and it is very difficult to perform even the simplest of tasks. So, in order to avoid this or to overcome this problem, what we have is an operating system. So, the operating system resides between the computer hardware and the users. So, it is an intermediary that acts between the computer hardware and the user. So, let us take our first example that we have taken. Suppose the user wants to type something and save it into his Microsoft Word. So, what he does, he just double clicks on that Microsoft Word. And then the rest of the things, the operating system takes care of it. It just opens it for him and then it makes the screen ready for him for typing. And whatever he types it, the operating system tells the hardware what to do. So that it will be typed and displayed on the screen. And everything that otherwise would have to be done manually by the user. is now taken care of by the operating system. And after typing it, he has to save it. When he saves it, the operating system tells the computer hardware where to save it and how to save it and how much memory to allocate for saving it. And everything is done by the operating system. So, all those minute things which we otherwise had to do in the absence of operating system is now done by the operating system. And it becomes very easy for the user to use the computer system. So, the user just opens the computer, he just takes or opens what he wants to use it and he just uses it. And all the underlying things that has to happen, all the communication that has to happen between the computer hardware and the user is taken care of by the operating system. It does all for the user and thus the computing or the usage of computer becomes very easy for the users because of the presence of the operating system. So, that is the main task of an operating system. Now if we look back at these two lines that we have written, now it will make sense and now you will understand what it actually means. So, let's read it once again. An operating system is a program that manages the computer hardware. Yes, we saw that the computer hardware, how its resources like CPU, memory, I O devices, everything is managed by the operating system now. And then it also provides a basis for application programs and acts as an intermediary between the computer user and the computer hardware. So, it provides a basis for the application programs. So, here we have our application programs and it is installed on the operating system. It provides a base for the application programs. And also it acts as an intermediary between the computer user and the computer hardware. So, here we have the users and here we have the hardware. And in the operating system it acts like an intermediary between the user and the hardware. Thus making the process of computation and the usage of computers seamless and very easy for the users. So, that is the main function of an operating system. And I hope that made you understand what... an operating system actually does. Now we will be seeing some of the types of operating systems that we have and also the functions of operating system and what are the goals that an operating system needs to achieve. So here I have some types of operating system. First one is batch operating system, then time sharing operating system, distributed operating system, network operating system, real-time operating system, multi-programming, multi-processing. and multitasking operating systems. So, it is not limited to just this but these are some main types of operating systems that we have. And don't worry even if you don't understand them, I will be doing another lecture where I will explain all the types of this operating system in a clear manner. I am just introducing this to you so that you just get used to the terms that we have here. So, all these types of operating system they perform in a different way based on the need that we have. So, just remember that much and you can keep these few points in mind. And then let's see what are the functions of OS. So, the main functions of OS are Number one is it is an interface between the user and the hardware. Yes, we just saw that right now. We have users here and we have the hardware here. And it acts like an interface between the user and the hardware. And then the second point is allocation of resources. So, I already told you what I mean by resources here. What we mean by resources are the hardware that we have like the central processing unit, the memory and the input output devices. So when a user or when different users wants to use the different resources, so they have to be allocated. Our resources are not unlimited, we have limited resources. That means we have limited hardware. So how these resources should be allocated to users in such a way that everybody gets their share and it performs in an efficient manner. All this is done by the operating system. So, it allocates resources to different users or different processes in a good manner. That is the function of the operating system. And then it does the management of memory, security etc. So, I told you even when we were typing this word processor, we have to first load it into the main memory. Then after typing it, it has to be saved into the secondary memory or the hard disk. So, don't worry if you don't understand what is main memory, secondary memory and all this. I will be... I am explaining all this to you in a clear way in the coming lectures. So, just want you to understand that how the memory is managed. So, how things are stored or where they are stored, everything is managed by the operating system. And how securely it is done, that is also managed by the operating system. So, these are some of the main functions of operating system. And now let us see what are the goals of an operating system. So, we have studied this much. Now we must... We can just assume what its goals can be. Number one is convenience. So, I told you in that example, if we were not having an operating system, how tedious or how tough it would be to execute even the smallest of tasks by the user. But having an operating system on top of our computer hardware makes it very easy for the user to communicate to the computer hardware. it becomes a very convenient thing for the user to have this operating system. So, the first goal of operating system is to provide convenience. And then the second point is efficiency. Now, what do we mean by efficiency? If you were not having the operating system and let's say we have different users trying to access these resources and how would you efficiently manage the resources that you should get this much resources or the other users should get this much resources. So, If you do it manually, it is going to be very tough and there is very less chance that you can efficiently manage it. So, operating system by taking care of all these allocations of resources and management of memory and everything, it provides you an efficient usage of your system. The first point is convenience and the second point is efficiency. So, many operating systems are designed mainly for convenience. Some are designed for efficiency. But most or we can say many of the operating systems are designed for both convenience as well as efficiency. So, these are the goals of operating system which we achieve by the functions of this operating system. So, in this lecture we have seen the types of OS. We have seen the functions of OS and we have seen what is the basic structure and the basic components we have in our computer system. And we see what the operating system actually does in order to make computation very easy for us. And we have also seen some examples of the operating systems that we widely use. So, I hope this was clear to you. This was just an introduction to just get you started so that you can know what an operating system actually is. And now you must be understanding how complex task the operating system must be performing. So, all the design of operating system and each and everything that we need to know about this operating system, we will be studying step by step in this lecture series. So, I hope this introduction was clear to you. Thank you for watching and see you in the next one.

So, it is equally important. And this subject, it consists mainly of theory as well as problems. So, we will first see the theory and also we will be solving the problems related to this subject. And we will see what this subject means.

and what we can learn from this subject. So, first of all, this is just an introduction to operating system. And we will see what this operating system actually means and what are the functions of this operating system. What are the types of operating systems that we have? And we will just try to get a brief idea of this subject.

Alright, so let's get started. So, here it says that an operating system also abbreviated as OS is a program that manages the computer hardware. and it also says it also provides a basis for application programs and acts as an intermediary between computer user and computer hardware.

So, before we understand these two lines, I will be explaining it to you with a diagram. So, before we go into this diagram, here are some examples of some operating systems that we widely use these days. First is your Windows.

So, you may be using Windows in your desktop or your laptops. So it is one of the famous operating systems used by many people. And also we have Linux and Ubuntu which are also two open source operating systems that are widely used in your desktops, laptops and other devices.

And then we have the Mac OS which is the operating system from Apple. So in their laptops or in their MacBooks they use the Mac OS X and then in the iPhones we find iOS operating systems. And then we have the very famous Android which you must be having in your phones. So, Android is one of the famous operating system that is used for your mobile devices.

Alright, so now before we try to understand these two lines that we have written here, let us take a diagram to understand the basic structure of a computer system so that we can understand what is an operating system and what does an operating system actually do. So, here I have a diagram which represents the basic structure. or the basic components of a computer system.

So, first of all in the lowermost level, we have the computer hardware. And what are computer hardware? Computer hardware, it consists of resources like CPU, which is a central processing unit, and then memory, and then the I.O.

devices, which means input-output devices. So, your resources like the processing units, your CPU, and also your memory. Memory consists of primary memory, like your RAMs and your secondary memory like your ROMs. So, these things also I will be explaining it in a detailed way in another lecture. So, let's first know that our memory as well as the I O devices.

I O devices means the input output devices. These are the devices that you use for either giving input to your system or for getting output out of your system. So, examples of input devices will include your devices like your keyboards, mouse, your microphones these are devices that you use for giving input into the system and then output devices would be that devices that you use for getting output out of your systems that would be your devices like monitors or speakers which gives you output or which shows you or makes you hear the output those are your output devices so all these things they fall under computer hardware so we generally refer them to as resources all right And then on top of this we have the operating system. But for now let us just forget this operating system for a while. Let us just assume that it is not there.

And then on top of this operating system we have the system or the application programs. Now there are two kinds of software we have which is system software and application software. And system software are the software that are used to directly modify or directly give some command to the computer hardware.

And operating system is also a kind of system software but let's not think about that and let's not get confused hearing that but let's mainly try to understand what are application programs. Application programs are the programs or softwares that are used to perform a specific task and that can be directly used by the user. And these are some examples that we have here.

First is a word processor. Word processors are like your Microsoft Office Word which are softwares used for making Document files, I believe that we have all used Microsoft Word. And then we have spreadsheets.

Spreadsheets are like your Microsoft Excel. Okay, that is used for making tabular data or for making some calculations in your tabular data. And then we have compilers. So, if you are a computer science student, you may be knowing what compilers are. So, compilers are the software that we use for writing our computer.

Codes like C++, C or Java are written into your compilers. And then we have the text editors. Text editors are editors used for modifying or writing text like your notepad, wordpad etc.

And then we have web browsers. Web browsers are the softwares that enable you to browse the web. Even as you are watching this video in YouTube, you may be using some web browser to view this. And examples of this are Google Chrome, Mozilla Firefox, Internet Explorer and so on.

So, this is not the only application program that we have. We have many many application programs. And these are just few examples I took to make you understand. So, these are the application programs we have. And on top of that we have the users.

That is like users like you and me who are trying to use these softwares for performing specific task. So, let us take a simple example that this user 1 He wants to use the word processor. Let's say it is Microsoft Office Word. So, he wants to use word for typing some documents and he wants to save it to his system. So, let's see how he does it.

So, we imagine that there is no operating system over here. We just have this user and the application programs and then the computer hardware. So, if he wants to write a document or if he wants to type something into Microsoft Word, then he has to type something into Microsoft Word. tell the computer hardware that he wants to do it.

Now how can he do it? Since there is no operating system, he has to explicitly tell the computer hardware what he wants to do in the form of code. So, he has to first open the Microsoft Word and he has to tell the computer hardware that I want to load Microsoft Word.

So, please load it into the main memory. And then after it is loaded, he has to type something. And when he types something, whatever he types, It has to be displayed on the monitor. He has to tell the computer hardware to do even that.

He has to tell, please display the things that I am typing on the computer screen or on the monitor. And then after doing all that, he has to save it. And even for saving it, you have to tell the computer hardware that yeah, I am done with all my typing. And now please save this file with a particular file name to my hard disk.

So, for each and every small or minute task you have to perform, you have to explicitly tell the computer hardware what to do and how do you communicate to it in the form of codes. You have to write source code, you have to write codes for each and everything that you have to perform. So we see that it is a very tedious task or it is a very difficult task to do this if there is no operating system.

You have to manually tell the computer hardware each and everything that you have to do. So if it was like this then nobody would actually use a computer system or At least common people would not use the computer system because it is such a tedious thing and it is very difficult to perform even the simplest of tasks. So, in order to avoid this or to overcome this problem, what we have is an operating system.

So, the operating system resides between the computer hardware and the users. So, it is an intermediary that acts between the computer hardware and the user. So, let us take our first example that we have taken. Suppose the user wants to type something and save it into his Microsoft Word. So, what he does, he just double clicks on that Microsoft Word.

And then the rest of the things, the operating system takes care of it. It just opens it for him and then it makes the screen ready for him for typing. And whatever he types it, the operating system tells the hardware what to do.

So that it will be typed and displayed on the screen. And everything that otherwise would have to be done manually by the user. is now taken care of by the operating system.

And after typing it, he has to save it. When he saves it, the operating system tells the computer hardware where to save it and how to save it and how much memory to allocate for saving it. And everything is done by the operating system.

So, all those minute things which we otherwise had to do in the absence of operating system is now done by the operating system. And it becomes very easy for the user to use the computer system. So, the user just opens the computer, he just takes or opens what he wants to use it and he just uses it. And all the underlying things that has to happen, all the communication that has to happen between the computer hardware and the user is taken care of by the operating system. It does all for the user and thus the computing or the usage of computer becomes very easy for the users because of the presence of the operating system.

So, that is the main task of an operating system. Now if we look back at these two lines that we have written, now it will make sense and now you will understand what it actually means. So, let's read it once again.

An operating system is a program that manages the computer hardware. Yes, we saw that the computer hardware, how its resources like CPU, memory, I O devices, everything is managed by the operating system now. And then it also provides a basis for application programs and acts as an intermediary between the computer user and the computer hardware. So, it provides a basis for the application programs. So, here we have our application programs and it is installed on the operating system.

It provides a base for the application programs. And also it acts as an intermediary between the computer user and the computer hardware. So, here we have the users and here we have the hardware. And in the operating system it acts like an intermediary between the user and the hardware. Thus making the process of computation and the usage of computers seamless and very easy for the users.

So, that is the main function of an operating system. And I hope that made you understand what... an operating system actually does. Now we will be seeing some of the types of operating systems that we have and also the functions of operating system and what are the goals that an operating system needs to achieve.

So here I have some types of operating system. First one is batch operating system, then time sharing operating system, distributed operating system, network operating system, real-time operating system, multi-programming, multi-processing. and multitasking operating systems.

So, it is not limited to just this but these are some main types of operating systems that we have. And don't worry even if you don't understand them, I will be doing another lecture where I will explain all the types of this operating system in a clear manner. I am just introducing this to you so that you just get used to the terms that we have here. So, all these types of operating system they perform in a different way based on the need that we have. So, just remember that much and you can keep these few points in mind.

And then let's see what are the functions of OS. So, the main functions of OS are Number one is it is an interface between the user and the hardware. Yes, we just saw that right now.

We have users here and we have the hardware here. And it acts like an interface between the user and the hardware. And then the second point is allocation of resources. So, I already told you what I mean by resources here.

What we mean by resources are the hardware that we have like the central processing unit, the memory and the input output devices. So when a user or when different users wants to use the different resources, so they have to be allocated. Our resources are not unlimited, we have limited resources. That means we have limited hardware.

So how these resources should be allocated to users in such a way that everybody gets their share and it performs in an efficient manner. All this is done by the operating system. So, it allocates resources to different users or different processes in a good manner. That is the function of the operating system.

And then it does the management of memory, security etc. So, I told you even when we were typing this word processor, we have to first load it into the main memory. Then after typing it, it has to be saved into the secondary memory or the hard disk.

So, don't worry if you don't understand what is main memory, secondary memory and all this. I will be... I am explaining all this to you in a clear way in the coming lectures.

So, just want you to understand that how the memory is managed. So, how things are stored or where they are stored, everything is managed by the operating system. And how securely it is done, that is also managed by the operating system. So, these are some of the main functions of operating system. And now let us see what are the goals of an operating system.

So, we have studied this much. Now we must... We can just assume what its goals can be.

Number one is convenience. So, I told you in that example, if we were not having an operating system, how tedious or how tough it would be to execute even the smallest of tasks by the user. But having an operating system on top of our computer hardware makes it very easy for the user to communicate to the computer hardware.

it becomes a very convenient thing for the user to have this operating system. So, the first goal of operating system is to provide convenience. And then the second point is efficiency. Now, what do we mean by efficiency? If you were not having the operating system and let's say we have different users trying to access these resources and how would you efficiently manage the resources that you should get this much resources or the other users should get this much resources.

So, If you do it manually, it is going to be very tough and there is very less chance that you can efficiently manage it. So, operating system by taking care of all these allocations of resources and management of memory and everything, it provides you an efficient usage of your system. The first point is convenience and the second point is efficiency.

So, many operating systems are designed mainly for convenience. Some are designed for efficiency. But most or we can say many of the operating systems are designed for both convenience as well as efficiency. So, these are the goals of operating system which we achieve by the functions of this operating system. So, in this lecture we have seen the types of OS.

We have seen the functions of OS and we have seen what is the basic structure and the basic components we have in our computer system. And we see what the operating system actually does in order to make computation very easy for us. And we have also seen some examples of the operating systems that we widely use. So, I hope this was clear to you.

This was just an introduction to just get you started so that you can know what an operating system actually is. And now you must be understanding how complex task the operating system must be performing. So, all the design of operating system and each and everything that we need to know about this operating system, we will be studying step by step in this lecture series. So, I hope this introduction was clear to you.

Thank you for watching and see you in the next one.

Transcript for:Introduction to Operating System

Transcript for:
Introduction to Operating System