SHREE LEARNING ACADEMY

Before going to the actual definition of an operating system, let us first ask ourselves, have we ever used an Operating System? Well i have used an operating system, and speaking of you, i am 100% sure that you have also used an operating system because currently for viewing this tutorial you are actually using an Operating System for example Windows, Mac OS, Linux or if you are using a mobile it can be Android or iOS there are dozens of operating systems out there and you could be using any one of them right now.

So now that we know we are familiar with operating systems and it is not an alien to us let us go to the definition of an operating system.

Definition:

The problem with this example is the communication gap between you and the computer hardware meaning that you don't know the language of computer and the computer doesn't know your human language.

A solution to this problem can be that you can learn computer languages so that you can instruct the computer and get your work done. But it is not that easy as it seems to be because computers understand the machine language or we can say the binary language or to make it more simpler 1 or 0, yes computers understand and work in 1 or 0 format that is the binary language. And it can be a tedious task to write hours of 1 or 0 code just to tell your computer to play your favourite song which is of barely 3 minutes length.
Hours of code just to play a 3 minute song is that really justice?
But then what's the solution?

Well, the solution is simple, we get a middleman for doing this tedious task, and that middleman is operating system.

Operating system understands the user's language and also the hardware language and therefore it bridges the gap between the user and the hardware so that work can be done effectively efficiently and easily.

From our daunting example come to the real world and ask your computer to play your favourite song with a few keyboard strikes or sometimes even your voice instruction and definitely your song will be played within seconds the reason is that your computer has operating system which knows how to do this job.

Remember a hardware without a software is barely a paper weight a big junky paper weight!!!

Coming back to the definition of operating systems let us next discuss what a kernel mode is

User Mode and Kernel Mode

There are generally two CPU modes, the user mode and the kernel mode.

The user mode is where the user runs his or her applications like the web browser, music player, word processor etc etc.

For the security sake the user mode does not have many privileges, to do a task it depends upon the permissions given by the operating system or the kernel mode which helps the user mode to run a particular application.

Where as the kernel mode has all the privileges and permissions which are required to run mostly all applications and even an operating system.

Therefore the user mode is also called as restricted mode and the kernel mode is called as unrestricted mode.

The reason for this difference between these two modes is first for security reasons because not all applications can be trusted, can be given all the powers to do changes into the computer and second due to this difference the operating system can work like a boss so that it can manage all the software and the hardware resources of the computer and therefore an operating system resides under kernel mode so that it can watch each and everything it can allow or restrict any software to run depending on the circumstances.

Let's sum up by visiting the operating system's definition once again.

"An Operating system is a system software which mostly works in kernel mode and manages all the Software and Hardware resources by bridging the gap between the system hardware and the user."

You may know what a system software means. There are generally two types of software, an application software and a system software. Application Software means your softwares like your web browser and your MP3 player, word processor etc etc. And the systems Software means the operating system.

"An Operating system is a system software which mostly works in kernel mode and manages all the Software and Hardware resources by bridging the gap between the system hardware and the user."

We just saw what a kernel mode is there are two types of CPU modes one the user mode and the 2nd is the kernel mode the user mode does not have many privileges or permissions to run a particular process and the kernel mode has all the privileges and Capabilities to run a particular task or process and therefore to manage all the resources operating system needs to reside into the kernel mode. User mode is also called restricted mode and kernel mode is also called unrestricted mode.

"An Operating system is a system software which mostly works in kernel mode and manages all the Software and Hardware resources by bridging the gap between the system hardware and the user."

Well , managing all these resources are very much important say for example you have a printer and 10 software wants to print 1000 pages simultaneously so without managing them the only thing which is going to happen is that few letters of the Print will be from software one and the next few letters would be from software 2 and so on and the final thing would be that a very much ugly and chaotic experience for the user and all those 1000 pages print will be of no use therefore we need an operating system to manage all our hardware and software resources the operating system will make a Queue of the softwares so these softwares can print their respective pages one by one and finally the user will get a neat and perfect print.

"An Operating system is a system software which mostly works in kernel mode and manages all the Software and Hardware resources by bridging the gap between the system hardware and the user."