Linux ( or ) is a family of

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s based on the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...

, an

operating system kernel The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. It is the portion of the operating system code that is always resident in memory and facilitates in ...

first released on September 17, 1991, by

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also c ...

. Linux is typically

packaged Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a co ...

as a

Linux distribution A Linux distribution (often abbreviated as distro) is an operating system made from a software collection that includes the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one ...

, which includes the kernel and supporting system software and libraries, many of which are provided by the

GNU Project The GNU Project () is a free software, mass collaboration project announced by Richard Stallman on September 27, 1983. Its goal is to give computer users freedom and control in their use of their computers and computing devices by collaborati ...

. Many Linux distributions use the word "Linux" in their name, but the

Free Software Foundation The Free Software Foundation (FSF) is a 501(c)#501(c)(3), 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed ...

uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include

Debian Debian (), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software, developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of D ...

, Fedora Linux, and

Ubuntu Ubuntu ( ) is a Linux distribution based on Debian and composed mostly of free and open-source software. Ubuntu is officially released in three editions: ''Desktop'', ''Server'', and ''Core'' for Internet of things devices and robots. All the ...

, the latter of which itself consists of many different distributions and modifications, including

Lubuntu Lubuntu ( ) is a lightweight Linux distribution based on Ubuntu and uses the LXQt desktop environment in place of Ubuntu's GNOME desktop. Lubuntu was originally touted as being "lighter, less resource hungry and more energy-efficient", but now ...

and

Xubuntu Xubuntu () is a Canonical Ltd.–recognized, community-maintained derivative of the Ubuntu operating system. The name ''Xubuntu'' is a portmanteau of ''Xfce'' and ''Ubuntu'', as it uses the Xfce desktop environment, instead of Ubuntu's Unity a ...

. Commercial distributions include

Red Hat Enterprise Linux Red Hat Enterprise Linux (RHEL) is a commercial open-source Linux distribution developed by Red Hat for the commercial market. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version ...

and

SUSE Linux Enterprise SUSE Linux Enterprise (often abbreviated to SLE) is a Linux-based operating system developed by SUSE. It is available in two editions, suffixed with Server (SLES) for servers and mainframes, and Desktop (SLED) for workstations and desktop comp ...

. Desktop Linux distributions include a

windowing system In computing, a windowing system (or window system) is software that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP (windows, icons, menus, pointer) paradigm for ...

such as X11 or Wayland, and a

desktop environment In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphica ...

such as

GNOME A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...

KDE Plasma Plasma is a desktop environment by KDE, and can refer to: * KDE Plasma 5 (2014–today) * KDE Plasma 4 (2008–2015) * Plasma Mobile for smartphones * Plasma Bigscreen Plasma Bigscreen is a software project from KDE which contains an interface op ...

. Distributions intended for servers may omit

graphics Graphics () are visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of data, as in design and manufacture ...

altogether, or include a

solution stack In computing, a solution stack or software stack is a set of software subsystems or components needed to create a complete Computing platform, platform such that no additional software is needed to support applications. Applications are said to " ...

such as

LAMP Lamp, Lamps or LAMP may refer to: Lighting * Oil lamp, using an oil-based fuel source * Kerosene lamp, using kerosene as a fuel * Electric lamp, or light bulb, a replaceable component that produces light from electricity * Light fixture, or ligh ...

. Because Linux is freely redistributable, anyone may create a distribution for any purpose. Linux was originally developed for

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

s based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system. Because of the dominance of the Linux-based

Android Android may refer to: Science and technology * Android (robot), a humanoid robot or synthetic organism designed to imitate a human * Android (operating system), Google's mobile operating system ** Bugdroid, a Google mascot sometimes referred to ...

smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...

s, Linux, including Android, has the largest

installed base Installed base (also install base, install ''ed'' user base or just user base) is a measure of the number of units of a product or service that are actually in use, as opposed to market share, which only reflects sales over a particular period. ...

of all

general-purpose operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s, . Although Linux is, , used by only around 2.6 percent of

desktop computer A desktop computer (often abbreviated desktop) is a personal computer designed for regular use at a single location on or near a desk due to its size and power requirements. The most common configuration has a case that houses the power supply ...

s, the Chromebook, which runs the Linux kernel-based ChromeOS, dominates the US

K–12 K–12, from kindergarten to 12th grade, is an American English expression that indicates the range of years of publicly supported primary and secondary education found in the United States, which is similar to publicly supported school grade ...

education market and represents nearly 20 percent of sub-$300

notebook A notebook (also known as a notepad, writing pad, drawing pad, or legal pad) is a book or stack of paper pages that are often ruled and used for purposes such as note-taking, journaling or other writing, drawing, or scrapbooking. History ...

sales in the US. Linux is the leading operating system on servers (over 96.4% of the top 1 million web servers' operating systems are Linux), leads other

big iron "Big Iron" is a country ballad written and performed by Marty Robbins, originally released as an album track on ''Gunfighter Ballads and Trail Songs'' in September 1959, then as a single in February 1960 with the song "Saddle Tramp" as the B-si ...

systems such as

mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...

s, and is used on all of the world's 500 fastest supercompters (since November 2017, having gradually displaced all competitors). Linux also runs on

embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...

s, i.e. devices whose operating system is typically built into the

firmware In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...

and is highly tailored to the system. This includes routers,

automation Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...

controls, smart home devices,

video game console A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can be played with a game controller. These may be home video game console, home consoles, which are generally placed i ...

television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...

s (Samsung and LG Smart TVs),

automobiles A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as ...

(Tesla, Audi, Mercedes-Benz, Hyundai and Toyota), and

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

( Falcon 9 rocket,

Dragon A dragon is a reptilian legendary creature that appears in the folklore of many cultures worldwide. Beliefs about dragons vary considerably through regions, but dragons in western cultures since the High Middle Ages have often been depicted as ...

crew capsule and the ''Perseverance'' rover). Linux is one of the most prominent examples of free and open-source

software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

collaboration. The

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

may be used, modified and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the

GNU General Public License The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

(GPL). The Linux kernel, for example, is licensed under the GPLv2.

History

Precursors

The

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

operating system was conceived and implemented in 1969, at

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile tel ...

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

, in the United States by Ken Thompson,

Dennis Ritchie Dennis MacAlistair Ritchie (September 9, 1941 – October 12, 2011) was an American computer scientist. He is most well-known for creating the C programming language and, with long-time colleague Ken Thompson, the Unix operating system and B p ...

, Douglas McIlroy, and

Joe Ossanna Joseph Frank Ossanna, Jr. (December 10, 1928 – November 28, 1977) was an electrical engineer and computer programmer who worked as a member of the technical staff at the Bell Labs, Bell Telephone Laboratories in Murray Hill, New Jersey. He be ...

. First released in 1971, Unix was written entirely in

assembly language In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...

, as was common practice at the time. In 1973, in a key pioneering approach, it was rewritten in the C programming language by Dennis Ritchie (with the exception of some hardware and I/O routines). The availability of a high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier

antitrust case In the United States, antitrust law is a collection of mostly federal laws that regulate the conduct and organization of businesses to promote competition and prevent unjustified monopolies. The three main U.S. antitrust statutes are the Sherman ...

forbidding it from entering the computer business, AT&T licensed the operating system's source code as a trade secret to anyone who asked. As a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of its regional operating companies, and was released from its obligation not to enter the computer business; freed of that obligation, Bell Labs began selling Unix as a

proprietary {{Short pages monitor LinuxWasch3

In the United States, the name ''Linux'' is a trademark registered to Linus Torvalds. Initially, nobody registered it, but on August 15, 1994, William R. Della Croce, Jr. filed for the trademark ''Linux'', and then demanded royalties from Linux distributors. In 1996, Torvalds and some affected organizations sued him to have the trademark assigned to Torvalds, and, in 1997, the case was settled. The licensing of the trademark has since been handled by the

Linux Mark Institute The Linux Mark Institute (LMI, fully "LMI Oregon, LLC") is an organization which administers the "''Linux''" trademark on behalf of Linus Torvalds for computer software which includes the Linux kernel, computer hardware utilizing Linux-based sof ...

(LMI). Torvalds has stated that he trademarked the name only to prevent someone else from using it. LMI originally charged a nominal sublicensing fee for use of the Linux name as part of trademarks, but later changed this in favor of offering a free, perpetual worldwide sublicense. The

(FSF) prefers ''GNU/Linux'' as the name when referring to the operating system as a whole, because it considers Linux distributions to be variants of the GNU operating system initiated in 1983 by

Richard Stallman Richard Matthew Stallman (; born March 16, 1953), also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to ...

, president of the FSF. They explicitly take no issue over the name Android for the Android OS, which is also an operating system based on the Linux kernel, as GNU is not a part of it. A minority of public figures and software projects other than Stallman and the FSF, notably

(which had been sponsored by the FSF up to 1996), also use ''GNU/Linux'' when referring to the operating system as a whole. Most media and common usage, however, refers to this family of operating systems simply as ''Linux'', as do many large Linux distributions (for example, SUSE Linux and

). By contrast, Linux distributions containing only free software use "GNU/Linux" or simply "GNU", such as Trisquel GNU/Linux,

Parabola GNU/Linux-libre Parabola GNU/Linux-libre is an operating system for the i686, x86-64 and ARMv7 architectures. It is based on many of the packages from Arch Linux and Arch Linux ARM, but distinguishes from the former by offering only free software. It includes th ...

BLAG Linux and GNU BLAG Linux and GNU is a discontinued Linux distribution made by the Brixton Linux Action Group. BLAG is a discontinued, single-CD distro with applications desktop users "expect" from a desktop including multimedia, graphics, desktop internet app ...

, and gNewSense. , about 8% to 13% of the lines of code of the Linux distribution Ubuntu (version "Natty") is made of GNU components (the range depending on whether

is considered part of GNU); meanwhile, 6% is taken by the Linux kernel, increased to 9% when including its direct dependencies. ( self-published data)

Notes

References

External links

*
Graphical map of Linux Internals

Linux kernel website and archives

The History of Linux in GIT Repository Format 1992–2010
{{Authority control 1991 software Computing platforms Cross-platform software Finnish inventions Free software programmed in C Linus Torvalds Operating systems Unix variants

History

Precursors

See also

Notes

References

External links