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{{two other uses|operating systems that use the Linux kernel|the kernel itself|Linux kernel|}}
{{Infobox OS
| logo =
| screenshot = ]
| caption = ] the penguin, mascot of Linux <ref name="LinuxOnLine2008">{{cite web|url = http://www.linux.org/info/logos.html|title = Linux Logos and Mascots|accessdate = 2009-08-11|last = Linux Online|authorlink = |year = 2008}}</ref>
| family = ]
| source_model = ]
| frequently_updated = yes
| kernel_type = ]
| userland = ] and others.
| supported_platforms = ], ], ], ], ], ], ], ], ], ], ], ], ] and more <!-- please do not include 64 bit extensions of 32 bit ISAs, e.g. sparc64, ppc64, x86-64, etc. -->
| license = Various including ], ], ], ], and others<ref>{{cite web | title = Debian GNU/Linux Licenses – Ohloh | url = https://www.ohloh.net/p/debian/analyses/latest | publisher = ohloh.net | accessdate = 2009-03-27 }}</ref>
| working_state = Current
}}
'''Linux''' (commonly {{pron-en|ˈlɪnʌks}}, {{respell|LI|nuks}} in English,<ref>{{cite web|url=http://safalra.com/science/linguistics/linux-pronunciation/|title=Pronunciation of ‘Linux’|last=Safalra|date=2007-04-14|work=Safalra’s Website|accessdate=2009-09-15}}</ref><ref name="Foldoc09Jun06">{{cite web|url = http://foldoc.org/linux|title = Linux|accessdate = 2009-09-15|last = Free On-Line Dictionary of Computing|authorlink = |year = 2006|month = June}}</ref> also {{pron-en|ˈlɪnʊks}}, {{respell|LI|nooks}}<ref>Torvalds used {{IPA|/ˈlɪnʊks/}} in English.<br/>{{ cite newsgroup | newsgroups = comp.os.linux | title = Re: How to pronounce "Linux"? | id = 1992Apr23.123216.22024@klaava.Helsinki.FI | date = 23 April 1992 | accessdate = 2007-01-09 }}<br/> Torvalds has made available an audio sample with his pronunciation in English ({{IPA|/ˈlɪnʊks/}}: {{cite web | url = http://www.paul.sladen.org/pronunciation/ | title = How to pronounce Linux? | accessdate = 2006-12-17 }}) and in Swedish ({{IPA|/ˈlɪːnɤks/}}: {{cite web | url = http://www.kernel.org/pub/linux/kernel/SillySounds/ | title = Linus pronouncing Linux in English and Swedish | accessdate = 2007-01-20 }}</ref>) is a generic term referring to ] computer ]s based on the ]. Their development is one of the most prominent examples of ] collaboration;{{Citation needed|date=November 2009}} typically all the underlying ] can be used, freely modified, and redistributed, both commercially and non-commercially, by anyone under licenses such as the ].


Linux is predominantly known for its use in ]s, although can be installed on a wide variety of computer ], ranging from ], mobile phones and even some watches<ref name="IBMLinuxWatch">{{cite web|url = http://www.trl.ibm.com/projects/ngm/wp10_e.htm|title = Linux Watch|accessdate = 2009-09-29|last = ]|authorlink = |year = 2001|month = October}}</ref> to ] and ].<ref>{{cite web | title = IBM's newest mainframe is all Linux | url = http://www.computerworld.com/s/article/9142007/IBM_s_newest_mainframe_is_all_Linux_ | last = Computerworld | first = Patrick Thibodeau | accessdate = 2009-02-22 }}</ref><ref>{{cite web | title = Linux rules supercomputers | url = http://www.forbes.com/home/enterprisetech/2005/03/15/cz_dl_0315linux.html | last = Lyons | first = Daniel | accessdate = 2007-02-22 }}</ref> ]s, installed on both desktop and laptop computers, have become increasingly commonplace in recent years, partly owing to the popular ] distribution<ref name="Economist">{{cite web|url = http://www.economist.com/science/displaystory.cfm?story_id=10410912|title = Technology in 2008|accessdate = 2008-04-01 (publicly available Dec 2007 – May 2009, rendered members only in May 2009, quoted at |last = The Economist|authorlink = |year = 2007|month = December}}</ref> and the emergence of ]s.<ref name="Economist04Dec08">{{cite news|url = http://www.economist.com/science/tq/displaystory.cfm?story_id=12673233|title = Small is beautiful|accessdate = 2008-12-21|last = ]|authorlink = |year = 2008|month = December}}</ref>
{{wilde|Why spend time getting actual work done when you can use all of it just to set up the computer?|Linux}}

'''Linux''' (pronounced {{IPA|}} LIN-ux; or {{IPA|}} LIE-nucks; or whatever the PR department decides to stick with at the time) is a term referring to any ] (OS) based on the Linux kernel. A fully-fledged Linux OS (or a "distribution") is usually designed to mimic the behavior of a UNIX-compliant operating system and for the IT department that is too much of a cheapskate to purchase anything properly certified. Despite its more orthodox uses in server deployment, Linux is also immensely popular amongst 1% of all desktop users worldwide and has a notorious reputation for causing spontaneous melting-point conflicts amongst users that outsiders simply could not care less about.
The name "Linux" comes from the Linux kernel, originally written in 1991 by ]. The full operating system usually comprises components such as ] and ] from the ] (announced in 1983 by ]), the ], the ] and ] ]s, and the ]. Commonly-used applications with desktop Linux systems include the ] web-browser and the ] office application suite. The GNU contribution is the basis for the ]'s preferred name '']''.<ref name="lsag">{{ cite book | url = http://www.tldp.org/LDP/sag/html/sag.html#GNU-OR-NOT | title = Linux System Administrator's Guide | chapter = 1.1 | edition = version 0.9 | date = 2004 | accessdate = 2007-01-18 | first = Alex | last = Weeks }}</ref><ref name="gnu_homepage">{{cite web|url=http://www.gnu.org/ |title=The GNU Operating System |publisher=Gnu.org |accessdate=2009-04-17}}</ref>


== History == == History ==
{{double image|right|Richard Matthew Stallman cropped.jpeg|150|Linus Torvalds cropped.jpeg|150|], left, founder of the ], and ], right, ] of the ]}}
{{wikipediapar|History of Linux}}
{{See also|History of Linux}}
The central code base of Linux (or the Linux "kernel") was largely the result of an small amateur project initiated by ], a small-time Finnish computer hobbyist yearning for recognition within a technological arena where most participants never took showers or left their parents' homes. Fueled with the passion for a free-of-charge version of Minix (which at the time was much in itself a throw-away operating system available at the cost of US$69), Torvalds decided to take on the challenge of spending sleepless nights with nothing but take-out food, hacked-together C code and a GNU C compiler. The result was the Linux kernel, followed by its announcement at Usenet newsgroup "comp.os.minix" purportedly via the following officially-sanctioned message:


===Unix===
{{cquote|Hello everybody out there using minix -
The ] operating system was conceived and implemented in 1969 at ]'s Bell Laboratories in the ] by ], ], ], and ]. It was first released in 1971 and was initially entirely written in ], a common practice at the time. Later, in a key pioneering approach in 1973, Unix was re-written in the programming language ] by ], (with exceptions to the kernel and I/O). The availability of an operating system written in a high-level language allowed easier ] to different computer platforms and Unix became widely adopted by academic institutions and businesses.


===GNU===
I'm doing a (free) operating system (just a hobby, won't be big and professional like GNU) for 386(486) AT clones. This has been brewing since april, and is starting to get ready. I'd like any feedback on things people like/dislike in minix, as my OS resembles it somewhat (same physical layout of the file-system (due to practical reasons) among other things).
The ], started in 1983 by ], had the goal of creating a "''complete Unix-compatible software system''" composed entirely of ]. Work began in 1984.<ref name="gnu_announce">{{cite web|url=http://www.gnu.org/gnu/initial-announcement.html |title=About the GNU Project – Initial Announcement |publisher=Gnu.org |date=2008-06-23 |accessdate=2009-03-09}}</ref> Later, in 1985, Stallman created the ] and wrote the ] (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, ]s, ]s, a ], and a windowing system) were completed, although low-level elements such as ]s, ]s, and the ] were stalled and incomplete.<ref name="gnu history">{{cite web|url=http://www.gnu.org/gnu/gnu-history.html |title=Overview of the GNU System |publisher=Gnu.org |date= |accessdate=2009-03-09}}</ref> Linus Torvalds has said that if the GNU kernel had been available at the time (1991), he would not have decided to write his own.<ref>{{cite web | url = http://people.fluidsignal.com/~luferbu/misc/Linus_vs_Tanenbaum.html | title = Linus vs. Tanenbaum debate }}</ref>


=== MINIX ===
I've currently ported bash(1.08) and gcc(1.40), and things seem to work. This implies that I'll get something practical within a few months, and I'd like to know what features most people would want. Any suggestions are welcome, but I won't promise I'll implement them :-)
], ] of the ] operating system]]


] was an inexpensive minimal ] operating system, designed for education in computer science, written by ] (now MINIX is ] and redesigned also for “serious” use).
Linus (torvalds@kruuna.helsinki.fi)


In 1991 while attending the ], Torvalds began to work on a non-commercial replacement for ],<ref>{{ cite newsgroup | title = What would you like to see most in minix? | newsgroup = comp.os.minix | id = 1991Aug25.205708.9541@klaava.Helsinki.FI | url = http://groups.google.com/group/comp.os.minix/msg/b813d52cbc5a044b | last = Torvalds | first = Linus | accessdate = 2006-09-09 }}</ref> which would eventually become the ].
PS. Yes – it's free of any minix code, and it has a multi-threaded fs. It is NOT portable (uses 386 task switching etc), and it probably never will support anything other than AT-harddisks, as that's all I have :-(.}}


Torvalds began the development of Linux on MINIX and applications written for MINIX were also used under Linux. Later Linux matured and it became possible for Linux to be developed under itself.<ref>{{cite news | title = Chicken and egg: How was the first linux gcc binary created?? | newsgroup = comp.os.minix | url = http://groups.google.com/group/comp.os.linux/msg/4ae6db18d3f49b0e }}</ref> Also GNU applications replaced all MINIX ones because, with code from the GNU system freely available, it was advantageous if this could be used with the fledgling OS. Code licensed under the GNU GPL can be used in other projects, so long as they also are released under the same or a compatible license. In order to make the Linux kernel compatible with the components from the GNU Project, Torvalds initiated a switch from his original license (which prohibited commercial redistribution) to the GNU GPL.<ref>{{cite web | title = Release notes for Linux v0.12 | first = Linus | last = Torvalds | url = http://www.kernel.org/pub/linux/kernel/Historic/old-versions/RELNOTES-0.12 | authorlink = Linus Torvalds | date = 1992-01-05 | accessdate = 2007-07-23 | publisher = Linux Kernel Archives | quote = The Linux copyright will change: I've had a couple of requests to make it compatible with the GNU copyleft, removing the “you may not distribute it for money” condition. I agree. I propose that the copyright be changed so that it confirms to GNU ─ pending approval of the persons who have helped write code. I assume this is going to be no problem for anybody: If you have grievances ("I wrote that code assuming the copyright would stay the same") mail me. Otherwise The GNU copyleft takes effect as of the first of February. If you do not know the gist of the GNU copyright ─ read it. }}</ref> Developers worked to integrate GNU components with Linux to make a fully functional and free operating system.<ref name="gnu history"/>
For years, the authenticity of the message has remained disputed, but it is only recently that a series of new discoveries has pointed the original newsgroup entry to a different text:


=== Commercial and popular uptake ===
{{cquote|"Hello every sucker out there using minix -
{{Main|Linux adoption}}
Today Linux distributions are used in numerous domains, from ]s to ]s,<ref>{{cite web | title = Linux system development on an embedded device | url = http://www-128.ibm.com/developerworks/library/l-embdev.html | first = Anand | last = Santhanam | coauthors = Vishal Kulkarni | work = DeveloperWorks | publisher = IBM | date = 1 March 2002 | accessdate = 2007-07-26 }}</ref><ref>{{cite web| last = Lyons | first = Daniel| title = Linux rules supercomputers | url = http://www.forbes.com/home/enterprisetech/2005/03/15/cz_dl_0315linux.html | accessdate = 2007-02-22}}</ref> and have secured a place in ] installations with the popular ] application stack.<ref>{{cite web| last = Schrecker| first = Michael| title = Turn on Web Interactivity with LAMP | url = http://www.techsoup.org/learningcenter/webbuilding/page5067.cfm | accessdate = 2007-02-22}}</ref> Use of Linux distributions in home and enterprise desktops has been expanding.<ref name="galli2007">{{cite news | first=Peter | last=Galli | coauthors= | title=Vista Aiding Linux Desktop, Strategist Says | date=2007-08-08 | publisher=Ziff Davis Enterprise Inc. | url =http://www.eweek.com/c/a/Linux-and-Open-Source/Vista-Aiding-Linux-Desktop-Strategist-Says/ | work =eWEEK | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="paul2007">{{cite news | first=Ryan | last=Paul | coauthors= | title=Linux market share set to surpass Win 98, OS X still ahead of Vista | date=2007-09-03 | publisher=Ars Technica, LLC | url =http://arstechnica.com/news.ars/post/20070903-linux-marketshare-set-to-surpass-windows-98.html | work =Ars Technica | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="beer2007">{{cite news | first=Stan | last=Beer | coauthors= | title=Vista to play second fiddle to XP until 2009: Gartner | date=2007-01-23 | publisher=iTWire | url =http://www.itwire.com.au/content/view/8842/53/ | work =iTWire | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="applications2007">{{cite web|url=http://marketshare.hitslink.com/report.aspx?qprid=2&qpmr=15&qpdt=1&qpct=3&qptimeframe=Y |title=Operating System Marketshare for Year 2007 |accessdate=2007-11-19 |date=2007-11-19 |work=Market Share |publisher=Net Applications }}</ref><ref name="xitimonitor2007">{{cite news | first= | last= | coauthors= | title=Vista slowly continues its growth; Linux more aggressive than Mac OS during the summer | date=2007-09-24 | publisher=AT Internet/XiTi.com | url =http://www.xitimonitor.com/en-us/internet-users-equipment/operating-systems-august-2007/index-1-2-7-107.html | work =XiTiMonitor | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="globalstats2007">{{cite web|url=http://www.w3counter.com/globalstats.php |title=Global Web Stats |accessdate=2007-11-19 |date=2007-11-10 |work=W3Counter |publisher=Awio Web Services LLC }}</ref><ref name="zeitgeist2004">{{cite web|url=http://www.google.com/press/zeitgeist/zeitgeist-jun04.html |title=June 2004 Zeitgeist |accessdate=2007-11-19 |date=2004-08-12 |work=Google Press Center |publisher=Google Inc. }}</ref> They have also gained popularity with various local and national governments. The federal government of Brazil is well known for its support for Linux.<ref>{{cite web | url = http://news.cnet.com/Brazils-love-of-Linux/2009-1042_3-6245409.html | title = Brazil's love of Linux | accessdate = 2009-02-21 }}</ref><ref>{{cite news | url = http://news.bbc.co.uk/2/hi/business/3445805.stm | title = Brazil falls in love with Linux | accessdate = 2009-02-21 | work=BBC News | date=2004-02-01}}</ref> News of the Russian military creating their own Linux distribution has also surfaced, and has come to fruition as the G.H.ost Project.<ref>{{cite web | url = http://www.osor.eu/news/lv-minister-open-standards-improve-efficiency-and-transparency | title = LV: Minister: "Open standards improve efficiency and transparency" | accessdate = 2009-02-21 }}</ref> Indian state of ] has gone so far as to make it mandatory for all state high schools to run Linux on their computers.<ref>{{cite web | url = http://www.businessweek.com/globalbiz/content/sep2006/gb20060921_463452.htm | title = Linux Spreads its Wings in India | accessdate = 2009-02-21 }}</ref><ref>{{cite web | url = http://www.indianexpress.com/news/kerala-shuts-windows-schools-to-use-only-linux/280323/0 | title = Kerala shuts windows, schools to use only Linux | accessdate = 2009-06-22 }}</ref> ] uses Linux exclusively as the operating system for its ] processor family to achieve technology independence.<ref>{{cite web | url = http://www.mdronline.com/watch/watch_Issue.asp?Volname=Issue+%23110308&on=1 | title = China’s Microprocessor Dilemma | accessdate = 2009-04-15 | publisher = ] }}</ref> In ] some regions have developed their own Linux distributions, which are widely used in education and official institutions, like ] in ] and ] in ]. ] and ] have also taken steps towards the adoption of Linux.<ref>{{cite web | url = http://seattlepi.nwsource.com/business/48925_linuxop01.shtml | title = Some countries are choosing Linux systems over Microsoft | accessdate = 2009-02-21 }}</ref>


Linux distributions have also become popular with the newly founded ] market, with many devices such as the ] and ] shipping with customized Linux distributions installed.{{Citation needed|date=November 2009}}
I'm doing a (probably-not-free) operating system (just a hobby, although I would like to be just as big and professional like other guys in the playing field) for 386(486) AT clones. This has been brewing since april, and is starting to get ready. I'd like to start a smear campaign on minix, as my OS resembles too much of it somewhat (same physical layout of the file-system amongst pretty much everything else).


=== Current development ===
I've currently ported bash(1.08) and gcc(1.40), and things seem to hold together instead of falling into a heap like they should. This implies that I'll get this fancy, repackaged minix crap done within a few months, and I'd like to know what sort of bones I should toss at the dogs. Any suggestions are welcome, but ] forbids I'll give a damn about them XD
Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of ]s.


== Design ==
Linus (torvalds@kruuna.helsinki.fi)
A Linux-based system is a modular ] operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Such a system uses a ], the ], which handles process control, networking, and ] and ] access. ] are integrated directly with the kernel.


Separate projects that interface with the kernel provide much of the system's higher-level functionality. The GNU ] is an important part of most Linux-based systems, providing the most common implementation of the ], a popular ], and many of the common ]s which carry out many basic operating system tasks. The ] (or GUI) used by most Linux systems is based on the ].
PS. Yes – sort of borrowed here and there from the minix code, but, hey, it has a multi-threaded fs! (Sort of...) It is NOT portable (uses 386 task switching etc), and it probably never will support anything other than AT-harddisks, but you can always stuff a few bucks in my pocket just to help things out a little. And, yeah, I know I am cute because I use ] a lot. And capitalizing is hard work :-(.}}


=== User interface ===
If proven genuine, this potentially vital record will not only explain the ego-driven nature of open-source projects in general, but also shed light on the sheer unreliability of most free software and the blooming of PayPal donation solicitation between 2000-2004. No respond thus far has been made by either Torvalds himself or the Free Software Foundation.
{{See also|User interface}}


Users can control a Linux-based system through a ] (or CLI), a ] (or GUI), or through controls attached to the associated hardware (this is common for embedded systems). For desktop systems, the default mode is usually graphical user interface, where the CLI is available through ] windows or on a separate ].
], a key figure in the core development of Linux. He's ], man.]]
=== Name and fame ===
Peculiarly, it was not Torvalds' intention to give his operating system the now-official name "Linux". For some time, Torvalds had been determined to call his project "Freex" (a portmanteau of "freak", "free", and "x") rather than the former as it was seen by himself as too "egotistical". However, when his co-worker at Helsinki University of Technology decided to go ahead and name his OS "Linux" anyway, Torvalds simply decided to exert absolutely no effort against his action. Today, the name "Linux" still signifies Torvalds' endeavor towards upholding his humble attitude, and although that other one Torvalds came up with never went beyond the confines of his computer's ATA hard disk drive, it still nevertheless describes the general appearances of the key figures in the core development of Linux quite aptly.


On desktop machines, ], ] and ] are the most popular user interfaces,<ref>{{cite web | title = Debian popularity-contest program information | url = http://times.debian.net/1092-30000-popcon-submissions }}</ref> though a variety of additional user interfaces exist. Most popular user interfaces run on top of the ] (often simply called "X"), which provides ], enabling a graphical application running on one machine to be displayed and controlled from another.{{Citation needed|date=November 2009}}
The attention Linux drew from commercial software developers was one of the key driving forces of the operating system's success. Red Hat rose to fame from a mere start-up company in the 1990's to one of the well-recognized figures in the providing of corporate system platforms. Canonical Inc. took the bulk of the work from the Debian project and repackaged it into what is now known as the Ubuntu OS. Despite being the legal owner of the Unix systems, Novell even jumped on the bandwagon and came up with SuSE Linux Enterprise Server. All these booms and busts raged on as Torvalds continued to spearhead his project under the banner of Free Software Foundation, and it was only a matter of time such developments of events brought about the inevitable.


Other GUIs include ]s such as ], ] and ]. The window manager provides a means to control the placement and appearance of individual application windows, and interacts with the X Window System. This is a more ] goal than KDE, GNOME et al., which are termed ]s.
]


A Linux system typically provides a CLI through a ], which is the traditional way of interacting with a Unix system. A Linux distribution specialized for servers may use the CLI as its only interface. A ] that runs without even a monitor can be controlled by the command line via a remote-control protocol such as ] or ].
=== Obligatory lawsuits ===
In a typical scenario of "getting even with the big wigs", the exchange of legal threats between commercial entities is much in itself an unavoidable process (e.g. ] v. <insert random start-up/community here>). Should a lawsuit become imminent, legal teams of each side will create reasons in a fashion not dissimilar to that observed in '']'' such that there ''are'' in fact ] involved in the case and that they have been stolen by those representing the other side. Indeed, the resultant costs to both of the opposing parties are usually in the magnitude of millions of dollars, and seldom these are incurred with the involvement of at least one attractive female legal aide that is seen in the aforementioned televised series, making such lawsuit completely meaningless if not downright boring.


Most low-level Linux components, including the GNU ], use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks, and provides very simple ]. A graphical ] program is often used to access the CLI from a Linux desktop.
According to lawyers from the SCO Group, some UNIX code was allegedly ported to Linux in fashions similar to the following:


== Development ==
<div style="margin: 20px; width: 90%; text-indent: 50px"><code style="font-size: large">mv SCO.unix.kernel linux</code></div>
] operating systems showing Linux's origins. Note that despite similar architectural designs and concepts being shared as part of the ] standard, Linux does not share any non-free source code with the original ] or ].]]
{{Main|Linux distribution}}


The primary difference between Linux and many other popular contemporary operating systems is that the ] and other components are ] and ]. Linux is not the only such operating system, although it is by far the most widely used.<ref name="MarketShare09NOV">{{cite web|url = http://marketshare.hitslink.com/operating-system-market-share.aspx?qprid=8|title = Operating System Market Share|accessdate = 2009-12-11|last = Operating System Market Share |authorlink = |year = 2009|month = November}}</ref>
As debates on the various aspects of the case intensified, Novell saw the opportunity of filing their own cheap-shot lawsuit against SCO Group and forced the latter into bankruptcy. Opinions regarding the debacle were generally negative and included:
Some ] and ] software licenses are based on the principle of ], a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license, the ], is a form of copyleft, and is used for the Linux kernel and many of the components from the ].


Linux based distributions are intended by developers for ] with other operating systems and established computing standards. Linux systems adhere to ],<ref>{{cite web | url = http://www.ukuug.org/newsletter/linux-newsletter/linux@uk21/posix.shtml | title = POSIX.1 (FIPS 151-2) Certification }}</ref> ],<ref>{{cite web | title = How source code compatible is Debian with other Unix systems? | url = http://www.debian.org/doc/FAQ/ch-compat.en.html#s-otherunices | work = Debian FAQ | publisher = the Debian project }}</ref> ] and ] standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT.<ref>{{cite web | url = http://www.linuxjournal.com/article/0131 | title = Certifying Linux }}</ref>
#that "Kernel programmers would have stolen from Solaris anyway",
#that "Linux works well", and
#that "mv wasn't implemented in 1991."


Free software projects, although developed in a ] fashion, are often produced independently of each other. The fact that the software licenses explicitly permit redistribution, however, provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a ].
== Design ==
] of all operating systems - if you get the drift.]]
The design of most Linux distributions is much centered about the way Torvalds envisioned it in the early 1990's. To understand this, simply picture a considerably large amount of Bobcats manned by intoxicated landfill workers trying to gather an assortment of plastic bags, empty cans and unspeakable refuse around and over a very large pile of used diapers. If the resultant odorous mass fails to withstand the gravitational forces and falls apart, then it is considered "unstable". Otherwise, it is deemed "stable". In a Linux distribution, the kernel is the pile of used diapers in the garbage heap, whereas the applications are the assortment of thrown-away items on the outside. Given this paradigm, there is virtually no need for Linux distribution developers to model or predict any user behaviors, and they are granted the liberty to pack anything and everything into the final release so as long as it does not trigger a catastrophic system failure at a click of the mouse. The freedom of speech is hence maximized in the distribution.


A ], commonly called a "distro", is a project that manages a remote collection of system software and application software packages available for download and installation through a network connection. This allows the user to adapt the operating system to his/her specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution can be installed using a CD that contains distribution-specific software for initial system installation and configuration. A package manager such as ] or ] allows later package upgrades and installations. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole.
]
=== Kernel ===
The Linux kernel is a ''very'' large <ref>Yep, much to the point that it simply imploded before .</ref>piece of software that sits between user applications and the physical hardware inside a computer. In contrast to the micro/hybrid kernel designs<ref>Speaking of the devil, can anyone say ""?</ref>, where drivers are often handled as a separate process under the operating system, Linux always attempts to absorb everything hardware-related to the kernel image in the main memory. This greatly increase the performance of the system since it offers better opportunity for the kernel itself to simply panic rather than have to seek ways to stop a misbehaving device driver from running. The modular driver adaptation feature found in Linux stock kernels also shortens the waiting period between downtimes by giving anonymous parties a tool to inject sophisticated custom code into a running system<ref>See example: .</ref>. With the stringent coding structure established amongst kernel developers, a fully open-source Linux distribution is practically fool-proof.


=== Community ===
Example kernel module (i.e. device driver) code:
{{See also|Free software community|Linux Users Group}}
<pre style="height: 200px; overflow: auto">
#include <stdlib.h>


A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, ] being a well-known example. Others maintain a community version of their commercial distributions, as ] does with ].
/*
* Inline documentation is a great place to express personal sentiments
* e.g. "I am going to kill whoever designed this piece of shit chip!"
*
* (Note that in a world where Linux reigned supreme, the response to
* this statement would likely be, according to linux-2.6.1/drivers/
* ieee1394/dv1394.c, "Why the hell not?")
*/


In many cities and regions, local associations known as ]s (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many ] communities also provide support to Linux users and developers. Most distributions and free software / open source projects have ] chatrooms or ]s. ]s are another means for support, with notable examples being ] and the ] forums. Linux distributions host ]s; commonly there will be a specific topic such as usage or development for a given list.
/*
* Do: make your variables as obscure and cryptic as possible
* Don't: be relevant
*/


There are several technology websites with a Linux focus. Print ]s on Linux often include ]s including software or even complete Linux distributions.<ref>{{cite web | url=http://www.linuxformat.co.uk/dvd/ | title=Linux Format DVD contents | author=] | accessdate=2008-01-17 }}</ref><ref>{{cite web | url=http://www.linux-magazine.com/resources/current_issue | title=Current Issue | author=] | accessdate=2008-01-17 }}</ref>
char linusTorvalds = "God";
char sayWhat = "whatever";
int penguinLanded = 2;


Although ] are generally available without charge, several large corporations sell, support, and contribute to the development of the components of the system and of ]. These include ], ], ], ], ], ], ]. A number of corporations, notably ], have built their entire business around Linux distributions.
/*
* Remember - this is your code. BE ORIGINAL!
* For example, why not liken a function to, say,
* having the enough fingers to cross
* (i.e. make the sign of good luck)?
*/


The ], on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as ]. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software in order to sell hardware.
void crossTheFingers (int fingers) {
int fingers = /dev/stdin.next();
int weAreScrewed = 0;


=== Programming on Linux ===
if (fingers <= 1) { weAreScrewed = 1; }
Most Linux distributions support dozens of ]s. The most common collection of utilities for building both Linux applications and operating system programs is found within the ], which includes the ] (GCC) and the ]. Amongst others, GCC provides compilers for ], ], ], ], and ]. The Linux kernel itself is written to be compiled with GCC. ] compilers for Linux include the ], ], and IBM XL C/C++ Compiler. ] is supported in such forms as ], ], and ].
else{ weAreScrewed = 0; }
}
/*
* (Note that extra geek creds are merited based on the number of
* fast food references used in the code. See
* http://www.gelato.unsw.edu.au/lxr/source/drivers/net/sunhme.c
* for a working example)
*/


Most distributions also include support for ], ], ], ] and other ]. While not as common, Linux also supports ] via the ] project, sponsored by ], and ]. A number of ]s and development kits run on Linux, including the original Sun Microsystems JVM (]), and IBM's J2SE RE, as well as many open-source projects like ].
/*
* Forget that Twitter nonsense - we have the Linux Kernel!
* Take your opportunity to make complaints about what
* other people did to the code IN the code like this guy
* did in linux-2.4.34/arch/parisc/kernel:
* "I don't know why everyone else assumes they can call this
* with a pointer to a stack_t on the kernel stack. That
* makes no sense. Anyway we'll do it like m68k, since we
* also are using segmentation in the same way as them."
*/


The two main frameworks for developing graphical applications are those of ] and ]. These projects are based on the ] and ] ]s, respectively, which can also be used independently of the larger framework. Both support a wide variety of languages. There are a number of ]s available including ], ], ], ], ], ], ], ] and ] while the long-established editors ] and ] remain popular.<ref>{{cite web | first = Joe | last = Brockmeier | title = A survey of Linux Web development tools | url = http://programming.linux.com/programming/05/10/03/1828224.shtml?tid=63&tid=47 | accessdate = 2006-12-16 }}</ref>
if(windows_on_partition)
{
delete_windows();
cout << "Windows deleted. Press ENTER to say sorry." << endl;
cin.getch();
telephone_bill_gates();
phonestream bill_gates_telephone;
bill_gates_telephone << "HAHA 1 computer now a victim of Linux";
}
/*
*If someone actually WANTS the driver,
*let's make sure it get them nowhere!
*/


== Uses ==
if(KEXT:Called(2))
As well as those designed for general purpose use on desktops and servers, distributions may be specialized for different purposes including: ] support, ], stability, security, localization to a specific region or language, targeting of specific user groups, support for ] applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only ]. Currently, over three hundred distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.<ref>{{cite web | url = http://lwn.net/Distributions/ | title = The LWN.net Linux Distribution List | accessdate = 2006-05-19 }}</ref>
{
pipe1 = pipe.open(/dev/stdin, /dev/null, /bin);
pipe1.send(/dev/null) << pipe1.recv(/dev/stdin, /bin);
}
</pre>


Linux is a widely ] operating system kernel. The Linux kernel runs on a highly diverse range of ]s: in the hand-held ]-based ] and the ] ] ], ] in devices ranging from ]s to ]s.<ref>{{cite web| url = http://www.freeos.com/articles/4737/ | title = If I could re-write Linux | first = Prakash | last = Advani | date = 8 February 2004 | accessdate = 2007-01-23 | publisher = freeos.com }}</ref> Specialized distributions exist for less mainstream architectures. The ] kernel ] can run on ] or ] ] microprocessors, while the ] kernel fork may run on systems without a ]. The kernel also runs on architectures that were only ever intended to use a manufacturer-created operating system, such as ] computers (with both ] and ] processors), ]s, ]s, ], and ]s.
=== UNIX-like ===
The central idea about Linux being UNIX-like is that it allows users to experience the glimpse of the general usability of a UNIX-compliant OS with the extra benefits of being completely ] and free for use/development. This central idea can also be broken down into several more granular ideas, with each being equally important against others. They include:


There are several industry associations and hardware ]s devoted to maintaining and improving support for diverse hardware under Linux, such as ].
{| class="wikitable"
|-
! style="padding: 5px" |Flexibility
| style="padding: 5px" |UNIX does not emphasize on a single unique application programming or user interface. Every developer is given their own freedom to base their own application on a standard of their own choice. This allows various coding/compilation standards to thrive simultaneously on the same computer platform, all 40 squillions of them.
|-
! style="padding: 5px" |Dependencies
| style="padding: 5px" |One key aspect of UNIX is its emphasis on dependencies. UNIX dependencies allow program libraries to glue together in a coherent manner and at the same time without imposing strict rules on what library packages an application is permitted to link to and what it is not. Hence, developers are free to make function calls to every function they can possibly find within the system and without following any form of abstraction standards, and users are to bear only, as a result, a slight cost of simply having to acquire a mighty collection of obscure packages required for their applications and recompile the kernel from scratch.
|-
! style="padding: 5px" |Individuality
| style="padding: 5px" |Instead of naming common directories and files "My Documents", "Program files" and "Command.com", UNIX has a more intuitive approach of handling nomenclatures. Firstly, UNIX does not simply handle plain data as files; under its design architecture, ''everything'' is essentially a file of some sort, even hardware. Secondly, it always tries to name everything in short hands. Thus, when a UNIX/UNIX-like system recognizes, say, a USB thumb drive, it will attempt to file it as a device node (i.e. a file representation of a device) under /dev and name it by the form of abstraction the device handling mechanism (e.g. udev) works with, say, "sd0" (i.e. SCSI disk/device 0) instead of what it ''actually'' is to the user. This gives the operating system an artistic attitude that makes every user stares at the monitor in utter bemusement.
|-
! style="padding: 5px" |Usability
| style="padding: 5px" |In UNIX, everything is about choice, and without it, freedom of speech will be undermined. Open-source developers are usually zealous in offering a substitute for every obscure software implementation even though there may have already been more than ten other functionally identical alternatives released under GPL before it. On the other hand, however, open-source developers do not usually ensure that there is any compelling reason for any person to disuse their working (and often non-free) solution and adopt such GPL'd offers. While configuring and operating open-source software via graphical interfaces often prove inadequate or simply impossible, users are often encouraged to employ a text-based command console as their standard user interface and plow through pages after pages obscure, jargon-filled, poorly written documentations in order to properly adjust their operating systems. Any user managed to live through such a process will be guaranteed an expert in computing.
|}


== Uses == === Desktop ===
]]]
=== Desktop Linux ===
]]]
]
]]]
==== Stare at it ====
{{Main|Desktop Linux}}
One major reason to install Linux is to offer oneself an alternative choice to simply ''stare'' at the PC instead of actually work at it. Really, on the ground of being completely free and open-source alone, there is simply no reason for one to complain even when OpenOffice/StarOffice simply does not read a Word document or a PowerPoint file correctly<ref>What do you expect from an office suite that soils its own pants simply for having more than in one paragraph anyway?</ref>, when that bloated Evolution suddenly gives up working<ref> </ref>, when the system freezes upon switching on that wireless card that almost every laptop computer has<ref>Don't worry, </ref>, or when yor 3D card fries up, or when someone puts a crippled sound subsystem in the distribution upgrade<ref> - "It works until you close the browser window".</ref>. Nevertheless, one can still always enjoy the leisure of playing with that spinning desktop cube thing, right? ''Right?''<ref>Oops, </ref>


The popularity of Linux on standard desktops (and laptops) has been increasing over the years.{{Citation needed|date=November 2009}} Currently most distributions include a graphical user environment. The two most popular such environments, ] and ], both of which are mature and support a wide variety of languages.
]


The performance of Linux on the desktop has been a controversial topic; for example in 2007 ] accused the Linux community of favoring performance on servers. He quit Linux kernel development because he was frustrated with this lack of focus on the desktop, and then gave a "tell all" interview on the topic.<ref>{{cite web|title=Linux: why I quit|url=http://apcmag.com/node/6735/|accessdate=2008-01-18|date=2007-07-24|work=APC Magazine|publisher=ACP Magazines}}</ref> Since then a significant effort has been expended improving the desktop experience. Projects such as ] aim for a faster boot time.<ref>{{cite web|title=Performance of Java on Ubuntu vs Windows|url=http://www.phoronix.com/scan.php?page=article&item=java_vm_performance&num=1}}</ref> In the field of ], the Linux desktop still lags behind Windows.<ref>{{Cite web|url=http://www.phoronix.com/scan.php?page=article&item=908&num=1 |title=A Synopsis Of Linux Graphics Drivers |author=Michael Larabel |date=9 November 2007 |accessdate=31 March 2009}}</ref> However, there are ] that do port their own or other companies' games to Linux.
==== Preach about it ====
One thing Linux users frequently do with their OS is to pander about it. When Torvalds woke up on ] one day, he received what he might refer to as a "divine message from above". Not realizing that what he was standing on was not even considered a planet anymore, he joyously jumped out of his moldy closet and decided that he had to make the world know that Linux is the future of computing technology<ref>Well, it has been said that "". This lunatic is definitely not kidding around.</ref>. He was given a generous amount of time, a total of more than 15 years, to fulfill his prophecy, but it was never materialized. Nevertheless, he gathered himself a sizable following that had somehow been convinced that a share of 1% of all desktop users <ref>''*insert your favorite laugh track *''</ref>could somehow garner from even the ] crowd more than simply a few chuckles or make people think there is actually a valid reason for programming a virus specifically targeted at Linux. Indeed, nothing is ever compelling enough to deter a zealous Linux user from yammering about how superior their OS is over Windows<ref>See also last subsection.</ref>.


Many types of applications available for ] and ] are also available for Linux. Commonly, either a ] application will exist which does the functions of an application found on another operating systems, or that application will have a version that works on Linux (such as ]). Furthermore, the ] project provides a Windows compatibility layer to run unmodified Windows applications on Linux. ] is a proprietary solution based on the open source ] project that supports running Windows versions of ], ] applications such as ] and ], ] versions through CS2, and many popular games such as '']'' and '']''. In other cases, where there is no Linux port of some software in areas such as ]<ref>{{cite web|url=http://www.freeos.com/articles/2540/ |title=Microsoft Office for Linux? |accessdate=2008-02-03 |last=Advani |first=Prakash |date=2000-10-27 |work=FreeOS |publisher=FreeOS Technologies (I) Pvt. Ltd. }}</ref> and ],<ref>{{cite web|url=http://arstechnica.com/guides/tweaks/linux-audio.ars |title=Editing audio in Linux |accessdate=2008-02-03 |last=Smith-Heisters |first=Ian |date=2005-10-11 |work=Ars Technica |publisher=Ars Technica, LLC }}</ref><ref>{{cite web|url=http://www.keyboardmag.com/article/linux-its-not/apr-07/27458 |title=Linux: It's Not Just For Computer Geeks Anymore |accessdate=2008-02-03 |last=Lumma |first=Carl |date=April 2007 |work=Keyboard Magazine |publisher=New Bay Media, LLC. }}</ref><ref>{{cite web|url=http://www.soundonsound.com/sos/feb04/articles/mirrorimage.htm |title=Using Linux For Recording & Mastering |accessdate=2008-02-03 |last=James |first=Daniel |date=February 2004 |work=Sound On Sound |publisher=SOS Publications Group }}</ref> there is equivalent software available on Linux.
]


Many popular applications are available for a wide variety of operating systems. For example ], and ] have downloadable versions for all major operating systems. Furthermore, some applications were initially developed for Linux (such as ], and ]) and, due to their popularity, were ported to other operating systems (including Windows and Mac OS X).
]


A growing number of proprietary desktop applications are also supported on Linux,<ref>{{cite web | url = http://www.iist.unu.edu/globaldesktop/ | title = The Global Desktop Project, Building Technology and Communities|accessdate = 2006-05-07 }}</ref> see ]. In the field of animation and visual effects, most high end software, such as ], Softimage XSI and ], is available for Linux, Windows and/or Mac OS X.
==== Work on it ====
Most Linux distributions possess an undocumented ability to generate a reality distortion field such that any user trapped within it is isolated from such influences of the real world as time-efficiency and cost-effectiveness. In such user's mind, all that is left are the inter-winded dependencies, the latest "almost-complete" FOSS alternative to a proprietary solution, the unmanageable aftermath left by the last distribution upgrade or the tedious "make install" thing that keeps failing again and again. To them, life should be about spending all day in front of a computer. It is like free speech, only without the actual talking-to-people part.


The collaborative nature of free software development allows distributed teams to ] Linux distributions for use in locales where localizing proprietary systems would not be cost-effective. For example the ] version of the ] distribution was available significantly before ] was translated to Sinhalese.{{Citation needed|date=April 2009}} In this case the Lanka Linux User Group played a major part in developing the localized system by combining the knowledge of university professors, ]s, and local developers.
=== Server Linux ===
] decided to develop an Enterprise Edition of their Linux distribution, what would it be named?]]
==== Do the "me too" ====
Despite the fall of the ] and end of ], there will always be people insisting that ] will ''eventually'' work. In a similar fashion, there will always be people insisting Linux and FOSS in general will ''some day'' replace proprietary software. Wild speculations aside, Red Hat did somehow manage to dominate a sizable portion of the server market for some time thanks to the low-cost "community"-oriented development strategy, and it was not long before other larger companies such as Novell<ref>And the Lord spake, "There shalt be Sue-Sahhh." And came to be. And it was a pile of </ref> and Oracle<ref>The "" Linux that is... Well, None other than itself.</ref> launched their own brand of Linux distributions as well. However, as many later realized, a "community" could operate in either one of the two modes: somewhat productive and completely unproductive. When a community generates absolutely nothing except hot steam and air, the sponsors lose their investment, and customers receive low-quality, half-baked products as a result. Nevertheless, community-based open-source projects are simply too hard a gravy train to not hitch a ride on even given that no one can predict if it will suddenly run off the rail at the next upgrade.


To install new software in Windows, users either download a digital distribution or use a traditional installation medium (such as CD-ROM). Both of these methods usually provide a "Software Installation Wizard" to guide the user through the setup. On most Linux distributions, there are utilities for browsing a list of thousands of applications installed with a single click. Some of these programs are the ], ], and ]. However, installing software not in the official repositories is not always easy, and sometimes the only option is to compile from source.
=== Embedded Linux ===
]
==== Harness the Voodoo ====
Embedding Linux to a portable device is one of the main goals to many established Linux communities. With the intricate layers of hardware and software abstractions, installing Linux to firmware can be as much challenging as balancing a stack of Jenga blocks on a chicken wire (and thus gives an extra ego boost to whoever taking it up). There have been successful examples of embedded Linux in wristwatches and appliances where open-source software choices are in only slightly short of a great demand, and as the new-generation smartphones become more and more popular, some distribution developers have even launched their mobile phone versions of Linux despite a general lack of interest in employing vi as an SMS editor and some considerable concern around finding the proper kernel patch for built-in cameras and actually making a phone call. Unless there is a general change of attitude in users towards open-source embedded devices, the opportunity for humankind to receive benefits as a result of the associated cosmic karma will remain doubtful.


=== Servers, mainframes and supercomputers ===
==Footnotes==
]
<small><references/></small>
] have long been used as ] operating systems, and have risen to prominence in that area; ] reported in September 2006 that eight of the ten most reliable internet hosting companies ran Linux distributions on their ]s.<ref>{{cite web | title = Rackspace Most Reliable Hoster in September | url = http://news.netcraft.com/archives/2006/10/07/rackspace_most_reliable_hoster_in_september.html | publisher = Netcraft | date = 7 October 2006 | accessdate = 2006-11-01}}</ref> (As of June 2008, Linux distributions represented five of ten, ] three of ten, and ] two of ten.<ref>{{cite web | title = Aplus.Net is the Most Reliable Hosting Company Site in June 2008 | url = http://news.netcraft.com/archives/2008/07/07/aplusnet_is_the_most_reliable_hosting_company_site_in_june_2008.html | publisher = Netcraft | date = 7 July 2008 | accessdate = 2008-07-28}}</ref>)

]'s ], as of November 2009 the world's fastest supercomputer. It uses the ] as its operating system.<ref name="CrayJag">{{cite web|url = http://www.top500.org/system/10184|title = Jaguar|accessdate = 2009-11-18|last = TOP500.Org|authorlink = |year = 2009}}</ref><ref name="NCCSJag">{{cite web|url = http://www.nccs.gov/computing-resources/jaguar/|title = Jaguar|accessdate = 2009-11-18|last = National Center for Computational Sciences|authorlink = |year = 2009|month = October}}</ref>]]
Linux distributions are the cornerstone of the ] server-software combination (Linux, ], ], ]/]/]) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.{{Citation needed|date=November 2009}}

] have become increasingly popular on ]s in the last decade due to pricing, compared to other mainframe operating systems. In December 2009, computer giant ] reported that it would predominantly market and sell mainframe-based Enterprise Linux Server.<ref name="The Register">{{cite web|author=Timothy Prickett Morgan|url=http://www.theregister.co.uk/2009/12/11/ibm_linux_only_mainframe/ |title=IBM punts Linux-only mainframes Big MIPS, deep discounts |publisher=The Register |date= |accessdate=2009-07-02}}</ref>

]s are also commonly used as ] for ]s: as of June 2009, out of the ] systems, 443 (88.6%) run a Linux distribution.<ref name="top500_osfam">{{cite web|author=TOP500.org |url=http://www.top500.org/stats/list/33/osfam |title=Operating system Family share for 06/2009 &#124; TOP500 Supercomputing Sites |publisher=Top500.org |date= |accessdate=2009-07-02}}</ref>

Linux was also selected as the operating system for the world's most powerful supercomputer, IBM's ] which will become operational in 2011.<ref name="IBM">{{cite web|url=http://www-03.ibm.com/press/us/en/pressrelease/26599.wss|title=20 Petaflop Sequoia Supercomputer}}</ref>

=== Embedded devices ===
{{See also|Embedded Linux|Linux devices}}
] running ]]]
Due to its low cost and ability to be easily modified, an ] is often used in ]. Linux has become a major competitor to the proprietary ] found in the majority of smartphones—16.7% of ]s sold worldwide during 2006 were using Linux<ref>{{cite web | url = http://www.informationweek.com/showArticle.jhtml?articleID=197000995 | title = The Palm OS Clings To Life }}</ref>—and it is an alternative to the proprietary ] and ] operating systems on ]s. Cell phones or PDAs running on Linux and built on open source platform became a trend from 2007, like ], ]'s ], Motorola RAZR2 v8, ], Motorola MING series, Motorola ZINE and the on-going ]. The popular ] digital video recorder uses a customized version of Linux.<ref>{{cite web | url = http://www.tivo.com/linux/linux.asp | title = TiVo ─ GNU/Linux Source Code | accessdate = 2006-12-12 |archiveurl=http://web.archive.org/web/20070519150730/http://www.tivo.com/linux/linux.asp |archivedate=2007-05-19}}</ref> Several network ] and ] standalone products, including several from ]/], use Linux internally, using its advanced firewall and routing capabilities. The ] and the ] ]s also run Linux.<ref>{{cite web |url=http://www.mvista.com/downloads/Case_study_MontaVista_Linux_and_Yamaha.pdf |title=Case Study: How MontaVista Linux helped Yamaha developers make a great product greater |accessdate=2007-08-26}}</ref> Furthermore, Linux is used in the leading ] control system, FlyingPig/HighEnd WholeHogIII Console.<ref>{{cite web | url=http://www.highend.com/products/controllers/Wholehog3Console.asp | title=Embedded Linux: FlyingPigs the WholeHogIII runs on Linux}}</ref>

=== Market share and uptake ===
{{Main|Linux adoption}}
Many quantitative studies of ] / open source software focus on topics including market share and reliability, with numerous studies specifically examining Linux.<ref>{{cite web | first = David A | last = Wheeler | url = http://www.dwheeler.com/oss_fs_why.html | title = Why Open Source Software/Free Software (OSS/FS)? Look at the Numbers! | accessdate = 2006-04-01 }}</ref> The Linux market is growing rapidly, and the revenue of servers, desktops, and packaged software running Linux was expected to exceed $35.7 billion by 2008.<ref>{{cite web | url = http://www.techweb.com/wire/showArticle.jhtml?articleID=55800522 | title = Linux To Ring Up $35 Billion By 2008 | accessdate = 2006-04-01 }}</ref>

]'s Q1 2007 report indicated that Linux held 12.7% of the overall server market at that time.<ref name="Linux-watch.com IDC's Q1 2007 report">{{cite web|url=http://www.linux-watch.com/news/NS5369154346.html |title=─ IDC Q1 2007 report |publisher=Linux-watch.com |date=2007-05-29 |accessdate=2009-03-09}}</ref> This estimate was based on the number of Linux servers sold by various companies and did not include server hardware purchased separately and had Linux installed on it later. In September 2008 Microsoft CEO ] admitted that 60% of web-servers run Linux versus 40% that run ].<ref name="PC World September 2008">
{{cite web|url = http://www.pcworld.com/businesscenter/article/151568/ballmer_still_searching_for_an_answer_to_google.html|title = Ballmer Still Searching for an Answer to Google|accessdate = 2009-06-04|last = Niccolai|first = James|authorlink = |year = 2008|month = September}}</ref>

Companies have, mostly based on web server statistics, estimated that the desktop market share of Linux range from less than 1% to 2.14%. In comparison, ] hold more than 85%.<ref name="galli2007"/><ref name="paul2007"/><ref name="beer2007"/><ref name="applications2007"/><ref name="xitimonitor2007"/><ref name="globalstats2007"/><ref name="zeitgeist2004"/><ref name="Byfield04May09">{{cite web|url = http://itmanagement.earthweb.com/osrc/article.php/12068_3818696_2/Linux-Desktop-Market-Share-Greater-Than-One-Percent.htm|title = Linux Desktop Market Share: Greater Than One Percent?|accessdate = 2009-05-06|last = Byfield|first = Bruce|authorlink = |year = 2009|month = May}}</ref><ref name="W3CCounterJuly09">{{cite web|url = http://www.w3counter.com/globalstats.php|title = W3Counter – Global Webstats|accessdate = 2009-08-22|last = Awio Web Services|authorlink = |year = 2009|month = August}}</ref>

The frictional cost of switching operating systems and lack of support for certain hardware and application programs designed for ] have been two factors that have inhibited adoption. Proponents and analysts attribute the relative success of Linux to its security, reliability,<ref>{{cite web | url = http://www-306.ibm.com/software/info/features/feb152005/ | title = Why customers are flocking to Linux }}</ref> low cost, and freedom from ].<ref>{{cite web | url = http://www.ca.com/za/news/2005/20051010_linux.htm| title = The rise and rise of Linux }}</ref>

Also most recently Google has begun to fund ], which acts as a compatibility layer, allowing users to run some Windows programs under Linux.<ref>{{cite mailing list |last=Kegel |first=Dan |url=http://article.gmane.org/gmane.comp.emulators.wine.devel/56872 |title=Google's support for Wine in 2007 |date=2008-02-14 |mailinglist=wine-devel |accessdate=2009-01-03}}</ref><ref>{{cite web
|url=http://code.google.com/opensource/wine.html
|title=Open Source Patches: Wine
|publisher=Google
|accessdate=2008-09-07
}}</ref>

The ] project of One Laptop Per Child is creating a new and potentially much larger Linux community, planned to reach millions of schoolchildren and their families and communities in developing countries.<ref>{{cite web|title=mission|url=http://www.laptop.org/en/vision/mission/index.shtml|publisher=laptop.org|accessdate=2008-08-14}}</ref> ], ], and ] are major supporters of the project.<ref></ref> While the XO will also have a Windows option, it will be primarily deployed using ], a desktop environment for ] Linux.

In the film industry, Linux has been the platform of choice for several years. The first major film produced on Linux servers was ] in 1997. Since then major studios like ], ] and ] have moved to Linux.<ref>{{cite web | url = http://www.linuxjournal.com/article/5472 | title = Industry of Change: Linux Storms Hollywood | accessdate = 2009-03-11 }}</ref><ref>{{cite web | url = http://video.fosdem.org/2008/maintracks/FOSDEM2008-tuxwithshades.ogg | title = Tux with Shades, Linux in Hollywood | accessdate = 2009-03-11 }}</ref> According to the Linux Movies Group, more than 95% of the servers and desktops at large animation and visual effects companies use Linux.<ref>{{cite web | url = http://www.linuxmovies.org/ | title = LinuxMovies.org – Advancing Linux Motion Picture Technology | accessdate = 2009-03-11 }}</ref>

{{See also|Usage share of desktop operating systems|List of Linux computers}}

== Copyright and naming ==
The Linux kernel and most GNU software are ]d under the ] (GPL). The GPL requires that anyone who distributes the Linux kernel must make the source code (and any modifications) available to the recipient under the same terms. In 1997, Linus Torvalds stated, “Making Linux GPL'd was definitely the best thing I ever did.”<ref>{{cite web | url = http://kde.sw.com.sg/food/linus.html | title = Linus Torvalds interview | accessdate = 2007-09-13 |archiveurl=http://web.archive.org/web/20070311190841/http://kde.sw.com.sg/food/linus.html |archivedate=2007-03-11}}</ref> Other key components of a Linux system may use other licenses; many libraries use the ] (LGPL), a more permissive variant of the GPL, and the ] uses the ].

Torvalds states that the Linux kernel will not move from version 2 of the GPL to version 3. He specifically dislikes some provisions in the new license which prohibit the use of the software in ],<ref>{{cite web | url=http://lkml.org/lkml/2006/1/25/273 | title=Re: GPL V3 and Linux ─ Dead Copyright Holders | author=Torvalds, Linus | date=2006-01-26 | publisher=]}}</ref><ref>{{cite web | url=http://lkml.org/lkml/2006/9/25/161 | title=Re: GPLv3 Position Statement | author=Torvalds, Linus | date=2006-09-25 | publisher=]}}</ref> and it would also be impractical to obtain permission from all the copyright holders, who number in the thousands.<ref></ref>

A 2001 study of ] 7.1 found that this distribution contained 30 million ].<ref name = "estimating_size"/> Using the ], the study estimated that this distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by conventional ] means, it would have cost about ${{formatprice|{{inflation|US|1080000000|2000}}|0}} ({{CURRENTISOYEAR}} US dollars) to develop in the United States.<ref name = "estimating_size">{{cite web | first = David A | last = Wheeler | date = 2002-07-29 | url = http://www.dwheeler.com/sloc/redhat71-v1/redhat71sloc.html | title = More Than a Gigabuck: Estimating GNU/Linux's Size | accessdate = 2006-05-11 }}</ref>

Most of the code (71%) was written in the ] ] ], but many other languages were used, including ], ], ], ], ], and various ]ing languages. Slightly over half of all lines of code were licensed under the GPL. The Linux kernel itself was 2.4 million lines of code, or 8% of the total.<ref name = "estimating_size"/>

In a later study, the same analysis was performed for ] version 4.0 (etch, released 2007).<ref>{{cite web | first = Juan José | last = Amor | coauthors = et al. | date = 17 June 2007 | url = https://penta.debconf.org/~joerg/attachments/33-measuring_etch_slides.pdf | title = Measuring Etch: the size of Debian 4.0 | accessdate = 2007-09-16 }}</ref> This distribution contained close to 283 million source lines of code, and the study estimated that it would have cost ${{formatprice|{{inflation|US|7170186240|2007}}|0}} ({{CURRENTISOYEAR}} US dollars) to develop by conventional means. <!-- original paper quoted 5358000000 euros, but Misplaced Pages does not have an inflation calculator for euros; converted to USD via June 17 2007 exchange rate as provided by http://www.bankofcanada.ca/en/rates/exchform.html and double-checked against other sources of historical exchange rates ... it is also more useful to quote the number in dollars, for comparison to other dollar amounts quoted in this article, e.g. the 2001 study above -->

In the United States, the name ''Linux'' is a trademark registered to Linus Torvalds.<ref>{{cite web | url = http://assignments.uspto.gov/assignments/q?db=tm&rno=1916230 | title = U.S. Reg No: 1916230 | publisher = United States Patent and Trademark Office | accessdate = 2006-04-01 }}</ref> Initially, nobody registered it, but on 15 August 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.<ref>{{cite web | url = http://www.linuxjournal.com/article/9065 | title = Linux Timeline | publisher = Linux Journal | date = 31 May 2006 }}</ref> The licensing of the trademark has since been handled by the ]. 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,<ref>{{cite news
| author = Neil McAllister
| title = Linus gets tough on Linux trademark
| url = http://www.infoworld.com/article/05/09/05/36OPopenent_1.html
| work = ]
| date = 2005-09-05
| accessdate = 2008-02-24
}}</ref> but later changed this in favor of offering a free, perpetual worldwide sublicense.<ref>{{cite web
| url = http://www.linuxmark.org
| title = Linux Mark Institute
| accessdate = 2008-02-24
| quote = LMI has restructured its sublicensing program. Our new sublicense agreement is: Free — approved sublicense holders pay no fees; Perpetual — sublicense terminates only in breach of the agreement or when your organization ceases to use its mark; Worldwide — one sublicense covers your use of the mark anywhere in the world
}}</ref>

{{See also|SCO-Linux controversies}}

=== GNU/Linux ===
{{Main|GNU/Linux naming controversy}}

The ] views Linux distributions which use GNU software as ] and they ask that such operating systems be referred to as ''GNU/Linux'' or ''a Linux-based GNU system''.<ref name="Stallman01">{{cite web | title = Linux and the GNU Project | url = http://www.gnu.org/gnu/linux-and-gnu.html | first = Richard | last = Stallman | authorlink = Richard Stallman | date = 2007-03-03 | accessdate = 2007-03-12 | publisher = Free Software Foundation }}</ref> The media and common usage, however, refers to this family of operating systems simply as ''Linux'', as do many large Linux distributions (e.g. ]<ref name="UbuntuHomePage">{{cite web|url = http://www.ubuntu.com/|title = About Ubuntu|accessdate = 2009-03-22|last = ]|authorlink = |year = 2009}}</ref> and ] Linux). Some distributions use ''GNU/Linux'' (particularly notable is ], on which Ubuntu is based), but the term's use outside of the enthusiast community is limited. The naming issue remains controversial.


== See also == == See also ==
{{Portal|Linux|NewTux.svg}}
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==References==
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== Further reading ==
{{wikiversity2|Operating Systems/GNU-Linux|Linux}}
* {{cite book|last=Weinberg|first=Bill|title=Uniting Mobile Linux Application Platforms|publisher=LinuxPundit.com|date=July 2008|pages=18|url=http://www.linuxpundit.com/cv/docs/Platforms_WP_LP.pdf}}


== External links == == External links ==
{{sisterlinks}}
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* (manages the Linux trade mark)
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;External links for readers new to Linux
*
* * a news feed of articles about Linux updated daily
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{{Linux}}
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{{FOSS}}
{{Operating system}}
{{Linux distributions}}


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Revision as of 19:14, 6 January 2010

Template:Two other uses

Operating system
Linux
Tux the penguin, mascot of Linux
OS familyUnix-like
Working stateCurrent
Source modelFree and open source software
PlatformsIA-32, MIPS, x86-64, SPARC, DEC Alpha, Itanium, PowerPC, ARM, m68k, PA-RISC, s390, SuperH, M32R and more
Kernel typeMonolithic
UserlandGNU and others.
LicenseVarious including GNU General Public License, BSD License, Apache License, MIT License, and others
Official websitekernel.org

Linux (commonly Template:Pron-en, LI-nuks in English, also Template:Pron-en, LI-nooks) is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed, both commercially and non-commercially, by anyone under licenses such as the GNU GPL.

Linux is predominantly known for its use in servers, although can be installed on a wide variety of computer hardware, ranging from embedded devices, mobile phones and even some watches to mainframes and supercomputers. Linux distributions, installed on both desktop and laptop computers, have become increasingly commonplace in recent years, partly owing to the popular Ubuntu distribution and the emergence of netbooks.

The name "Linux" comes from the Linux kernel, originally written in 1991 by Linus Torvalds. The full operating system usually comprises components such as utilities and libraries from the GNU Project (announced in 1983 by Richard Stallman), the X Window System, the GNOME and KDE desktop environments, and the Apache HTTP Server. Commonly-used applications with desktop Linux systems include the Mozilla Firefox web-browser and the OpenOffice.org office application suite. The GNU contribution is the basis for the Free Software Foundation's preferred name GNU/Linux.

History

See also: History of Linux

Unix

The Unix operating system was conceived and implemented in 1969 at AT&T's Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna. It was first released in 1971 and was initially entirely written in assembly language, a common practice at the time. Later, in a key pioneering approach in 1973, Unix was re-written in the programming language C by Dennis Ritchie, (with exceptions to the kernel and I/O). The availability of an operating system written in a high-level language allowed easier portability to different computer platforms and Unix became widely adopted by academic institutions and businesses.

GNU

The GNU Project, started in 1983 by Richard Stallman, had the goal of creating a "complete Unix-compatible software system" composed entirely of free software. Work began in 1984. Later, in 1985, Stallman created the Free Software Foundation and wrote the GNU General Public License (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, compilers, text editors, a Unix shell, and a windowing system) were completed, although low-level elements such as device drivers, daemons, and the kernel were stalled and incomplete. Linus Torvalds has said that if the GNU kernel had been available at the time (1991), he would not have decided to write his own.

MINIX

Andrew S. Tanenbaum, author of the MINIX operating system

MINIX was an inexpensive minimal Unix-like operating system, designed for education in computer science, written by Andrew S. Tanenbaum (now MINIX is free and redesigned also for “serious” use).

In 1991 while attending the University of Helsinki, Torvalds began to work on a non-commercial replacement for MINIX, which would eventually become the Linux kernel.

Torvalds began the development of Linux on MINIX and applications written for MINIX were also used under Linux. Later Linux matured and it became possible for Linux to be developed under itself. Also GNU applications replaced all MINIX ones because, with code from the GNU system freely available, it was advantageous if this could be used with the fledgling OS. Code licensed under the GNU GPL can be used in other projects, so long as they also are released under the same or a compatible license. In order to make the Linux kernel compatible with the components from the GNU Project, Torvalds initiated a switch from his original license (which prohibited commercial redistribution) to the GNU GPL. Developers worked to integrate GNU components with Linux to make a fully functional and free operating system.

Commercial and popular uptake

Main article: Linux adoption

Today Linux distributions are used in numerous domains, from embedded systems to supercomputers, and have secured a place in server installations with the popular LAMP application stack. Use of Linux distributions in home and enterprise desktops has been expanding. They have also gained popularity with various local and national governments. The federal government of Brazil is well known for its support for Linux. News of the Russian military creating their own Linux distribution has also surfaced, and has come to fruition as the G.H.ost Project. Indian state of Kerala has gone so far as to make it mandatory for all state high schools to run Linux on their computers. China uses Linux exclusively as the operating system for its Loongson processor family to achieve technology independence. In Spain some regions have developed their own Linux distributions, which are widely used in education and official institutions, like gnuLinEx in Extremadura and Guadalinex in Andalusia. France and Germany have also taken steps towards the adoption of Linux.

Linux distributions have also become popular with the newly founded netbook market, with many devices such as the ASUS Eee PC and Acer Aspire One shipping with customized Linux distributions installed.

Current development

Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions.

Design

A Linux-based system is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Such a system uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access. Device drivers are integrated directly with the kernel.

Separate projects that interface with the kernel provide much of the system's higher-level functionality. The GNU userland is an important part of most Linux-based systems, providing the most common implementation of the C library, a popular shell, and many of the common Unix tools which carry out many basic operating system tasks. The graphical user interface (or GUI) used by most Linux systems is based on the X Window System.

User interface

See also: User interface

Users can control a Linux-based system through a command line interface (or CLI), a graphical user interface (or GUI), or through controls attached to the associated hardware (this is common for embedded systems). For desktop systems, the default mode is usually graphical user interface, where the CLI is available through terminal emulator windows or on a separate virtual console.

On desktop machines, KDE, GNOME and Xfce are the most popular user interfaces, though a variety of additional user interfaces exist. Most popular user interfaces run on top of the X Window System (often simply called "X"), which provides network transparency, enabling a graphical application running on one machine to be displayed and controlled from another.

Other GUIs include X window managers such as FVWM, Enlightenment and Window Maker. The window manager provides a means to control the placement and appearance of individual application windows, and interacts with the X Window System. This is a more minimalist goal than KDE, GNOME et al., which are termed desktop environments.

A Linux system typically provides a CLI through a shell, which is the traditional way of interacting with a Unix system. A Linux distribution specialized for servers may use the CLI as its only interface. A headless system that runs without even a monitor can be controlled by the command line via a remote-control protocol such as SSH or telnet.

Most low-level Linux components, including the GNU userland, use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks, and provides very simple inter-process communication. A graphical terminal emulator program is often used to access the CLI from a Linux desktop.

Development

A summarized history of Unix-like operating systems showing Linux's origins. Note that despite similar architectural designs and concepts being shared as part of the POSIX standard, Linux does not share any non-free source code with the original Unix or MINIX.
Main article: Linux distribution

The primary difference between Linux and many other popular contemporary operating systems is that the Linux kernel and other components are free and open source software. Linux is not the only such operating system, although it is by far the most widely used. Some free and open source software licenses are based on the principle of copyleft, a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license, the GNU GPL, is a form of copyleft, and is used for the Linux kernel and many of the components from the GNU project.

Linux based distributions are intended by developers for interoperability with other operating systems and established computing standards. Linux systems adhere to POSIX, SUS, ISO and ANSI standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT.

Free software projects, although developed in a collaborative fashion, are often produced independently of each other. The fact that the software licenses explicitly permit redistribution, however, provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution.

A Linux distribution, commonly called a "distro", is a project that manages a remote collection of system software and application software packages available for download and installation through a network connection. This allows the user to adapt the operating system to his/her specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution can be installed using a CD that contains distribution-specific software for initial system installation and configuration. A package manager such as Synaptic or YAST allows later package upgrades and installations. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole.

Community

See also: Free software community and Linux Users Group

A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as Red Hat does with Fedora.

In many cities and regions, local associations known as Linux Users Groups (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many Internet communities also provide support to Linux users and developers. Most distributions and free software / open source projects have IRC chatrooms or newsgroups. Online forums are another means for support, with notable examples being LinuxQuestions.org and the Gentoo forums. Linux distributions host mailing lists; commonly there will be a specific topic such as usage or development for a given list.

There are several technology websites with a Linux focus. Print magazines on Linux often include cover disks including software or even complete Linux distributions.

Although Linux distributions are generally available without charge, several large corporations sell, support, and contribute to the development of the components of the system and of free software. These include Dell, IBM, HP, Oracle, Sun Microsystems, Novell, Nokia. A number of corporations, notably Red Hat, have built their entire business around Linux distributions.

The free software licenses, on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as symbiotic. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software in order to sell hardware.

Programming on Linux

Most Linux distributions support dozens of programming languages. The most common collection of utilities for building both Linux applications and operating system programs is found within the GNU toolchain, which includes the GNU Compiler Collection (GCC) and the GNU build system. Amongst others, GCC provides compilers for Ada, C, C++, Java, and Fortran. The Linux kernel itself is written to be compiled with GCC. Proprietary compilers for Linux include the Intel C++ Compiler, Sun Studio, and IBM XL C/C++ Compiler. BASIC is supported in such forms as Gambas, FreeBASIC, and XBasic.

Most distributions also include support for PHP, Perl, Ruby, Python and other dynamic languages. While not as common, Linux also supports C# via the Mono project, sponsored by Novell, and Scheme. A number of Java Virtual Machines and development kits run on Linux, including the original Sun Microsystems JVM (HotSpot), and IBM's J2SE RE, as well as many open-source projects like Kaffe.

The two main frameworks for developing graphical applications are those of GNOME and KDE. These projects are based on the GTK+ and Qt widget toolkits, respectively, which can also be used independently of the larger framework. Both support a wide variety of languages. There are a number of Integrated development environments available including Anjuta, Code::Blocks, Eclipse, KDevelop, Lazarus, MonoDevelop, NetBeans, QtCreator and Omnis Studio while the long-established editors Vim and Emacs remain popular.

Uses

As well as those designed for general purpose use on desktops and servers, distributions may be specialized for different purposes including: computer architecture support, embedded systems, stability, security, localization to a specific region or language, targeting of specific user groups, support for real-time applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only free software. Currently, over three hundred distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.

Linux is a widely ported operating system kernel. The Linux kernel runs on a highly diverse range of computer architectures: in the hand-held ARM-based iPAQ and the mainframe IBM System z9, System z10 in devices ranging from mobile phones to supercomputers. Specialized distributions exist for less mainstream architectures. The ELKS kernel fork can run on Intel 8086 or Intel 80286 16-bit microprocessors, while the µClinux kernel fork may run on systems without a memory management unit. The kernel also runs on architectures that were only ever intended to use a manufacturer-created operating system, such as Macintosh computers (with both PowerPC and Intel processors), PDAs, video game consoles, portable music players, and mobile phones.

There are several industry associations and hardware conferences devoted to maintaining and improving support for diverse hardware under Linux, such as FreedomHEC.

Desktop

GNOME
KDE
Xfce
Main article: Desktop Linux

The popularity of Linux on standard desktops (and laptops) has been increasing over the years. Currently most distributions include a graphical user environment. The two most popular such environments, GNOME and KDE, both of which are mature and support a wide variety of languages.

The performance of Linux on the desktop has been a controversial topic; for example in 2007 Con Kolivas accused the Linux community of favoring performance on servers. He quit Linux kernel development because he was frustrated with this lack of focus on the desktop, and then gave a "tell all" interview on the topic. Since then a significant effort has been expended improving the desktop experience. Projects such as upstart aim for a faster boot time. In the field of gaming, the Linux desktop still lags behind Windows. However, there are several companies that do port their own or other companies' games to Linux.

Many types of applications available for Microsoft Windows and Mac OS X are also available for Linux. Commonly, either a free software application will exist which does the functions of an application found on another operating systems, or that application will have a version that works on Linux (such as Skype). Furthermore, the Wine project provides a Windows compatibility layer to run unmodified Windows applications on Linux. CrossOver is a proprietary solution based on the open source Wine project that supports running Windows versions of Microsoft Office, Intuit applications such as Quicken and QuickBooks, Adobe Photoshop versions through CS2, and many popular games such as World of Warcraft and Team Fortress 2. In other cases, where there is no Linux port of some software in areas such as desktop publishing and professional audio, there is equivalent software available on Linux.

Many popular applications are available for a wide variety of operating systems. For example Mozilla Firefox, and OpenOffice.org have downloadable versions for all major operating systems. Furthermore, some applications were initially developed for Linux (such as Pidgin, and GIMP) and, due to their popularity, were ported to other operating systems (including Windows and Mac OS X).

A growing number of proprietary desktop applications are also supported on Linux, see List of proprietary software for Linux. In the field of animation and visual effects, most high end software, such as AutoDesk Maya, Softimage XSI and Apple Shake, is available for Linux, Windows and/or Mac OS X.

The collaborative nature of free software development allows distributed teams to localize Linux distributions for use in locales where localizing proprietary systems would not be cost-effective. For example the Sinhalese language version of the Knoppix distribution was available significantly before Microsoft Windows XP was translated to Sinhalese. In this case the Lanka Linux User Group played a major part in developing the localized system by combining the knowledge of university professors, linguists, and local developers.

To install new software in Windows, users either download a digital distribution or use a traditional installation medium (such as CD-ROM). Both of these methods usually provide a "Software Installation Wizard" to guide the user through the setup. On most Linux distributions, there are utilities for browsing a list of thousands of applications installed with a single click. Some of these programs are the Synaptic Package Manager, PackageKit, and Yum Extender. However, installing software not in the official repositories is not always easy, and sometimes the only option is to compile from source.

Servers, mainframes and supercomputers

Servers designed for Linux

Linux distributions have long been used as server operating systems, and have risen to prominence in that area; Netcraft reported in September 2006 that eight of the ten most reliable internet hosting companies ran Linux distributions on their web servers. (As of June 2008, Linux distributions represented five of ten, FreeBSD three of ten, and Microsoft two of ten.)

File:JaguarXT5.jpg
The Oak Ridge National Laboratory's Jaguar supercomputer, as of November 2009 the world's fastest supercomputer. It uses the Cray Linux Environment as its operating system.

Linux distributions are the cornerstone of the LAMP server-software combination (Linux, Apache, MySQL, Perl/PHP/Python) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.

Linux distributions have become increasingly popular on mainframes in the last decade due to pricing, compared to other mainframe operating systems. In December 2009, computer giant IBM reported that it would predominantly market and sell mainframe-based Enterprise Linux Server.

Linux distributions are also commonly used as operating systems for supercomputers: as of June 2009, out of the top 500 systems, 443 (88.6%) run a Linux distribution.

Linux was also selected as the operating system for the world's most powerful supercomputer, IBM's Sequoia which will become operational in 2011.

Embedded devices

See also: Embedded Linux and Linux devices
An HTC Dream running Android

Due to its low cost and ability to be easily modified, an embedded Linux is often used in embedded systems. Linux has become a major competitor to the proprietary Symbian OS found in the majority of smartphones—16.7% of smartphones sold worldwide during 2006 were using Linux—and it is an alternative to the proprietary Windows CE and Palm OS operating systems on mobile devices. Cell phones or PDAs running on Linux and built on open source platform became a trend from 2007, like Nokia N810, Openmoko's Neo1973, Motorola RAZR2 v8, Motorola ROKR E8, Motorola MING series, Motorola ZINE and the on-going Google Android. The popular TiVo digital video recorder uses a customized version of Linux. Several network firewall and router standalone products, including several from Cisco/Linksys, use Linux internally, using its advanced firewall and routing capabilities. The Korg OASYS and the Yamaha Motif XS music workstations also run Linux. Furthermore, Linux is used in the leading stage lighting control system, FlyingPig/HighEnd WholeHogIII Console.

Market share and uptake

Main article: Linux adoption

Many quantitative studies of free / open source software focus on topics including market share and reliability, with numerous studies specifically examining Linux. The Linux market is growing rapidly, and the revenue of servers, desktops, and packaged software running Linux was expected to exceed $35.7 billion by 2008.

IDC's Q1 2007 report indicated that Linux held 12.7% of the overall server market at that time. This estimate was based on the number of Linux servers sold by various companies and did not include server hardware purchased separately and had Linux installed on it later. In September 2008 Microsoft CEO Steve Ballmer admitted that 60% of web-servers run Linux versus 40% that run Windows Server.

Companies have, mostly based on web server statistics, estimated that the desktop market share of Linux range from less than 1% to 2.14%. In comparison, Microsoft operating systems hold more than 85%.

The frictional cost of switching operating systems and lack of support for certain hardware and application programs designed for Microsoft Windows have been two factors that have inhibited adoption. Proponents and analysts attribute the relative success of Linux to its security, reliability, low cost, and freedom from vendor lock-in.

Also most recently Google has begun to fund Wine, which acts as a compatibility layer, allowing users to run some Windows programs under Linux.

The XO laptop project of One Laptop Per Child is creating a new and potentially much larger Linux community, planned to reach millions of schoolchildren and their families and communities in developing countries. Google, Red Hat, and eBay are major supporters of the project. While the XO will also have a Windows option, it will be primarily deployed using Sugar, a desktop environment for Fedora Linux.

In the film industry, Linux has been the platform of choice for several years. The first major film produced on Linux servers was Titanic in 1997. Since then major studios like Dreamworks Animation, Pixar and Industrial Light & Magic have moved to Linux. According to the Linux Movies Group, more than 95% of the servers and desktops at large animation and visual effects companies use Linux.

See also: Usage share of desktop operating systems

Copyright and naming

The Linux kernel and most GNU software are licensed under the GNU General Public License (GPL). The GPL requires that anyone who distributes the Linux kernel must make the source code (and any modifications) available to the recipient under the same terms. In 1997, Linus Torvalds stated, “Making Linux GPL'd was definitely the best thing I ever did.” Other key components of a Linux system may use other licenses; many libraries use the GNU Lesser General Public License (LGPL), a more permissive variant of the GPL, and the X Window System uses the MIT License.

Torvalds states that the Linux kernel will not move from version 2 of the GPL to version 3. He specifically dislikes some provisions in the new license which prohibit the use of the software in digital rights management, and it would also be impractical to obtain permission from all the copyright holders, who number in the thousands.

A 2001 study of Red Hat Linux 7.1 found that this distribution contained 30 million source lines of code. Using the Constructive Cost Model, the study estimated that this distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by conventional proprietary means, it would have cost about $1.91 billion (2025 US dollars) to develop in the United States.

Most of the code (71%) was written in the C programming language, but many other languages were used, including C++, assembly language, Perl, Python, Fortran, and various shell scripting languages. Slightly over half of all lines of code were licensed under the GPL. The Linux kernel itself was 2.4 million lines of code, or 8% of the total.

In a later study, the same analysis was performed for Debian GNU/Linux version 4.0 (etch, released 2007). This distribution contained close to 283 million source lines of code, and the study estimated that it would have cost $10.5 billion (2025 US dollars) to develop by conventional means.

In the United States, the name Linux is a trademark registered to Linus Torvalds. Initially, nobody registered it, but on 15 August 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. 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.

See also: SCO-Linux controversies

GNU/Linux

Main article: GNU/Linux naming controversy

The Free Software Foundation views Linux distributions which use GNU software as GNU variants and they ask that such operating systems be referred to as GNU/Linux or a Linux-based GNU system. The media and common usage, however, refers to this family of operating systems simply as Linux, as do many large Linux distributions (e.g. Ubuntu and SuSE Linux). Some distributions use GNU/Linux (particularly notable is Debian GNU/Linux, on which Ubuntu is based), but the term's use outside of the enthusiast community is limited. The naming issue remains controversial.

See also

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References

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