Linux is an open-source operating system based on Linux kernel[Unix-like], and the OS kernel was first published on 17 September 1991 by Linus Torvalds. Typically, Linux is packaged as the Linux distribution[distro], which contains the supporting libraries and system software and kernel, several of which are offered by the GNU Project. Several Linux distributions use the term “Linux” in the title, but the Free Software Foundation uses the “GNU/Linux” title to focus on the necessity of GNU software.
Famous Linux distributions are Ubuntu, Fedora Linux, and Debian, the latter of which is composed of several different modifications and distributions, including Xubuntu and Lubuntu. Commercial distributions are SUSE Linux Enterprise and Red Hat Enterprise Linux.
Linux was first designed for personal computers that were Intel x86 architecture-based, but it has since been moved to more environments than other operating systems.
Android also use Linux kernel.
Also, Linux executes on many embedded systems, i.e., devices whose OS is typically designed into the firmware and is extremely customized to the system.
Linus is used in spacecraft (Perseverance rover, Dragon crew capsule, and Falcon 9 rocket), automobiles (Toyota, Hyundai, Mercedes-Benz, Audi, and Tesla), televisions (LG and Samsung Smart TVs), video game consoles, smart home devices, automation controls, and routers.
Basic Features of Linux
Portable − Portability means software can works on different types of hardware in same way. Linux kernel and application programs supports their installation on any kind of hardware platform.
Open Source − Linux source code is freely available and it is community based development project. Multiple teams work in collaboration to enhance the capability of Linux operating system and it is continuously evolving.
Multi-User − Linux is a multiuser system means multiple users can access system resources like memory/ ram/ application programs at same time.
Multiprogramming − Linux is a multiprogramming system means multiple applications can run at same time.
Hierarchical File System − Linux provides a standard file structure in which system files/ user files are arranged.
Shell − Linux provides a special interpreter program which can be used to execute commands of the operating system. It can be used to do various types of operations, call application programs. etc.
Security − Linux provides user security using authentication features like password protection/ controlled access to specific files/ encryption of data.
Architecture
The architecture of a Linux System consists of the following layers −
Hardware layer − Hardware consists of all peripheral devices (RAM/ HDD/ CPU etc).
Kernel − It is the core component of Operating System, interacts directly with hardware, provides low level services to upper layer components.
Shell − An interface to kernel, hiding complexity of kernel’s functions from users. The shell takes commands from the user and executes kernel’s functions.
Utilities − Utility programs that provide the user most of the functionalities of an operating systems.
