As a beginner, you should know about some basic details of Linux which are described well in this blog. Linux is an operating system such as Windows, Mac. This topic includes an introduction to Linux, a brief description of Linux kernel, various Linux versions which are used worldwide commercially or non-commercially, the design and user interfaces of Linux.

What is Linux?

Linux is an unix-like, free & open source operating system. Unix-like means, it is based on UNIX operating system. Linux is developed by Linus Torvalds in 1991. In 1990’s MINIX is unix based operating system which is used worldwide. But people want some advance features in this operating system. After this, Torvalds started working on Linux. Torvalds wanted to be named as “Freax”. In earlier months of development, he saved all his Linux files under the name “Freax”. But for further development, he has to use the FTP server of the University of Helsinki. They didn’t find the name suitable for use, so they changed the name of the project to “Linux” without consulting Torvalds and after that, it became famous as “LINUX”.

Free and open source means that it is free i.e., its license is free to avail, use, copy and change the software. Open source means that its basic source code is open to all and easily available.

FTP stands for File Transfer Protocol. It is a protocol used by the network during transmission of a file from client machine to the server and vice-versa.

Linux Kernel

The main component of Linux is its kernel. A kernel of any operating system is computer program that manages the communication between the computer applications and the hardware (CPU, Memory etc.) used by these applications. The kernel is a chip that tells the program what to do. Linux kernel is a monolithic kernel. Whenever the system boots, the bootloader stores all the kernel programs to the main memory. Without kernel operating system is nothing and without programs kernel is nothing.

BOOTLOADER is a piece of program code which boots the OS kernel files and configures the system to its initial known state.

Linux Distributions

Many operating systems were developed based on Linux. Since it is open source, anyone can create a new operating system on Linux under GNU General Public License. These different operating systems based on Linux are called Linux Distributions (also called as Distros).

Various distros are developed for different use. For computer systems these are, Ubuntu, Linux Mint, Fedora, Debian, CentOS, Kali, Slackware, etc. For server and commercial use these are, Red Hat Enterprise Linux (RHEL) and SUSE Linux Enterprise Server. Linux Distros are also developed for smartphones, netbooks, and other wireless devices such as Android, Mer, Tizen, etc. Linux systems are used in every domain, from embedded systems to supercomputers to wearables devices.

Linux was also adopted by NASA to replace their expensive machines to less expensive computers running on Linux.

Linux distros made their place in servers by using the secured application stack called “LAMP”.

An organization, Valve Corporation is working on Linux gaming distros for gaming purposes.

LAMP is a combination of Linux, Apache, MySQL and PHP. All of this combined and made an open source platform for dynamic web development.

Design and User interface

Linux operating system is Unix-like in design. The Linux kernel uses the monolithic kernel which is designed for process scheduling, memory management, handling virtual files and a network subsystem. The design helps in integrating the kernel with the device drivers. Linux design mainly consist two modes: User Mode and Kernel Mode.

Linux system includes, a boot-loader such as GRUB used to load kernel into main memory at the time of system booting, an init program such as system which is launched without the knowledge of user at the time of the starting any process such as system services and login prompts, software libraries which are required during the execution of any process such as libraries that contain system defined function definitions in C standard library.

DAEMONS are small computer programs run in background without interacting with the user. They usually run at the starting of a boot process.

GRUB- Grub is a type of boot-loader which allows multiboot system. A user can select in between multiple kernel configurations or operating system according to the need of a user.

User interface which is also known as shell is of two types:

• Command Line Interface (CLI) , which is a text-based interface. The inputs in this interface are in text (called commands) and the output is also obtained in the text. There are various distros available that are commands based only.
• Graphical User Interface , which is a graphics based interface. Various graphics are developed to make it more user-friendly. There are various distros available that contains some graphics. The GUI is developed by various widget toolkits, some of the toolkits are GTK+ by GNOME, Clutter, Qt by Qt project.

SUMMARY

This post defines the brief explanation of Linux operating system. The basic introduction of Linux, the Kernel used by Linux, various versions of Linux released worldwide, its design and the interfaces to interact with users. This gives you the cardinal knowledge of Linux to take the first step towards it. A major part of Linux is written in C programming languages. 97 percent of the world’s supercomputers use Linux. Approximately, 34 percent of the world runs on Linux servers. World’s No. one supercomputer “Tianhe-2” with the performance speed of 33.86 petaflops uses “Kylin” which is Linux-based operating system. World’s largest online store “Amazon” runs Linux on 97 percent of their web-facing computers. As discussed earlier, the main component of Linux is its Kernel which is explained in detail on next blog.

In the upcoming tutorial, we would discuss about detailed architecture of Linus. Stay tuned till then….

About the Author –

  Abhishek Wahi has expertise in Linux, Virtulization, Open Stack and AWS.