# Abstract

Linux is not an operating system, it is the kernel of the operating system.

Each operating system has its own kernel such as Windows's NT, Mac OS's XNU and Android, Ubuntu, Parrot OS, Fedora, BlackArch, Manejaro, Kali Linux, Arch etc. These are the most popular Linux based distro. Also, These operating systems have been created based on the Linux kernel. Linux is the kernel of those operating systems.

Clarification of the Linux kernel :

A computer is basically a collection of some hardware or parts. Its processor, memory, various peripheral devices, monitors, keyboards, mouse- these are all lifeless hardware. Even if they are connected and left all day, they will not be able to communicate with each other, will not be able to connect to electricity. Communication is a thing of the past, they will not know each other, they will not know anything about each other's existence.

So, these are different types of components made for different jobs, how do they all work together so much? What is such a beautiful understanding between them? And software means some instructions that tell that hardware to work one by one. How is this possible?

As soon as a computer is turned on, there is a lot of work to be done. There is no intelligence in this. The computer will do those things as soon as it gets an electricity connection. This is called start-up work. A software program will load into the computer's memory immediately after startup. You can't stop it if you want to just like a fool, without any instructions from you, as a specific step of a task will come and load in a certain area of ​​memory. This software program is called the operating system.

The operating system is another software program, similar to the other software programs we create. But the peculiarity of this is that the program will be placed in such a way that it can be loaded automatically first of all. Then all the other programs actually run their way under this operating system, so that they do not interfere with each other. The operating system itself reigns over the whole computer, the guardianship says, occupying it.

Another feature of the operating system is that its responsibilities are divided into two parts. As a result, there are two main components to this program that share those two types of responsibilities. One of these two parts is called the kernel.

The kernel communicates between computer hardware components and application software.

An operating system is a program and a part of it is a kernel. The kernel's operations are largely hardware-centric. E.g.-

Recognize hardware through various driver applications and coordinate between them. To mediate for the exchange of instructions with them. Manage the instructions received from the application software to suit the hardware. Taking care of computer memory and processor. To give authority to whom and when and how much time and space should be given. Coordinate between other application programs and processes. Delivering the signals from the hardware to the application software in a comprehensible manner. Without an operating system, all application software would have to understand the hardware at its own risk and adjust itself. Similarly, other processes in an operating system have made their work easier by following the kernel's preceptor. Without it, they would all have to understand hardware. It is a responsibility-sharing system. And the kernel itself is an organizational system, but it has been set aside to pay special attention to special responsibilities.

Where the kernel portion is loaded into memory, no outsiders have access. Located in the safest location, it dominates the entire computer world, keeps others in check, and makes it easy for them to understand the complexity of electronic devices called computers.

As soon as the computer starts up, the instructions that start running and finish the task by loading the kernel into memory are called "bootloader". The bootloader program is located on a specific block of the hard disk drive, called the "boot sector". The address of this boot sector is written in the computer's BIOS. As soon as the power button is pressed, the BIOS is controlled, he sees the address of the boot sector and runs the bootloader from there. The bootloader leaves the kernel in memory. Along with this, several application programs also started running. From then on, whatever we do with this computer, it has a meaning, when an event occurs, someone sees it, seeks the meaning of it, according to what they are told to say, gets instruction from them, output comes from there.

# The Linux kernel

It is a monolithic system. Although monolithic, it has different subsystems for different functions. The entire Linux kernel program is open-source and freely distributed.

The Linux kernel is compatible with a variety of embedded computers, mobile or wearable computers, servers, and supercomputers, as it works on our everyday PCs. It is the most widely used kernel program in the world.

Linux is like called Unix, but not Unix. Linus Torvalds is the visionary, author, and chief programmer of the Linux Kernel program. He started writing it in 1991. Although the Linux kernel started its journey with just a few C-files, by 2020 it had become a program of about 27.8 million lines of code.

Peace be upon you. Thanks a lot for reading until to finish this article. Rahat.