Linux

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Linux (kent as GNU/Linux an aw) is a Unix-like computer operatin seestem. It is ane o the maist kenspeckle examplars o open soorce development an free saftware; unlike proprietary operatin seestems sic as Microsoft Windaes or Mac OS X, its unnerlyin soorce code is tae haunde for onybody tae uise, chynge, an caw aboot for nae chairge.

First developit an uised tae the maist pairt by single enthusiasts on personal computers, Linux haes nou gained the support o muckle companies sic as IBM, Sun Microsystems, Hewlett-Packard, an Novell, Inc., an haes risen tae prominence as an operating seestem for servers; aicht o the ten maist reliable internet hostin companies nou rins Linux on their wab servers.[1]

Linux haes been mair widely portit tae deifferent computin platforms nor ony ither operating seestem. It is uised in devices reengin frae supercomputers tae mobile phones, an is gainin popularity in the personal computer mercat.[2]

Table o contents

[edit] History

Linus Torvalds, creator o the Linux kirnel.
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Linus Torvalds, creator o the Linux kirnel.

In 1983, Richard Stallman foondit the GNU Project, wi the ettle o developin a complete Unix-like operatin seestem composed haily o free saftware. By the stairt o the 1990s, GNU haed creatit or collectit maist o the necessar components o this seestem — librars, compilers, text editors, a Unix shell — except for the core component, the kirnel. The GNU project stairtit developin a kernel, the GNU Hurd, in 1990, foodit on the Mach microkernel, but the development o this Mach-based design haes pruiven gey hard an proceedit slaw.

In atween times, in 1991, anither kirnel wis begoud as a habby by Finnish university student Linus Torvalds while attendin the University o Helsinki.[3] Torvalds originally uised Minix on his ain computer, a simplifee'd Unix-like seestem written by Andrew Tanenbaum for learnin operatin seestem design. Forby thon Tanenbaum didna allou ithers tar rax his operatin seestem, leadin Torvalds tae big a replacement for Minix.

Originally, Torvalds cried his kirnel "Freax" for "free" an "freak" an wi the aften-uised X in the names o Unix-like seestems. The name "Linux" wis cleckit by Ari Lemmke, wha admeenistert an FTP server aucht the Finnish University Network; he cleckit the name Linux for the directory that Torvalds' project wis first tae hund for dounlade frae.[4]

Image:Unix.svg
A graphic history o Unix seestems. Linux is a Unix-type seestem but its soorce code daena descend frae the oreeginal Unix.

At first a computer rinnin Minix wis necessar for tae confeegur an instaw Linux. Ineetial versions o Linux needit anither operating seestem tae be present for tae boot frae a hard disk, but suin there war independent boot laders sic as LILO. The Linux seestem quickly surpassed Minix in functionality; Torvalds an ither early Linux kirnel developers adaptit their wark for the GNU components an uiser-space programmes for tae create a hale, fully functional, an free operating seestem.

The day, Torvalds conteenas tae guide the oncome o the kirnel, while ither subseestems sic as the GNU components conteeas tae be developed separate (Linux kernel development isna pairt o the GNU Project). Ither groups an companies combines an distributes thir components wi addeetional application saftware in the form o Linux distributions.

[edit] Portability

see also: Linux (kirnel) / Portabeelity

The Linux kirnel wis oreeginally designed anerly for Intel 80386 microprocessors, but nou uphauds a braid hatter o computer architectures. Linux is ane o the maist waften portit operating seestems, rinnin on a diverse reenge o seestems frae the haund-hauden ARM-based iPAQ tae the mainframe IBM System z9. Speecialized deestributions exists for less mainstream architectures.

[edit] Copyricht, licensin, an the Linux tredemerk

The Linux kirnel an maist GNU saftware is licensed unner the GNU General Public License. The GPL requires that aw deestributit soorce code modifications an derived warks be licensed unner the GPL an aw, an is whiles cried a "share an share-alike" or "copyleft" license. Qho Linus Torvalds in 1997 "Making Linux GPL'd was definitely the best thing I ever did."[5] Ither saftware micht uise ither licenses; mony librars uises the GNU Lesser General Public License (LGPL), a mair permissive variant o the GPL, an the X Window System uises the MIT License.

In the Unitit States, the name Linux is a tredemerk[6] registert tae Linus Torvalds. Initially, naebody registert it, but on August 15, 1994, William R. Della Croce, Jr. filed for the tredemerk Linux, an syne demaundit ryalties frae Linux deestributors. In 1996, Torvald an a wheen affectit organizations sued for tae hae the tredemerk assigned tae Torvalds, an in 1997 the case wis settelt[7]. The licensin o the tredemerk is nou haundelt bi the Linux Mark Institute. Torvalds haes statit that he juist tredemerkit the name for tae hinder ither bodies frae uisin it, but wis bund in 2005 bi Unitit States tredemerk law tae tak active meisurs tae uphaud the tredemerk. The affcome wis that the LMI sent oot a nummer o letters tae deestribution vendors speirin that a fee be paid for the uiss o the name, an a wheen companies haes complee'd.[8]

[edit] Pronunciation

In 1992, Torvalds expponed hou he soonds the wird Linux: Template:Cquotetxt

A soond file o Torvalds sayin "Hello, this is Linus Torvalds, and I pronounce Linux as Linux" can be fund here. Merk that in English, "Linux" an "Minix" is for ordinar soodit wi a cutty i (IPA: /ɪ/) soond that differs frae Torvalds' Finland-Swedish soondin o thir wirds, seemilar tae the differ atween the Finland-Swadish an English soondins o "Linus." The Finland-Swedish soondin {IPA /'linʌks/} hauds tae Scots phonology an aw.

[edit] Linux an the GNU Project

Richard Stallman, founder of the GNU project for a free operating system.
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Richard Stallman, founder of the GNU project for a free operating system.
Main airticle: GNU/Linux naming controversy

The ettle of the GNU project is tae produce a Unix-compatible operatin seestem conseestin haily o free saftware, an maist general-purpose Linux distributions relies on GNU librars an tuils written tae that effect. The Free Software Foundation sees thir Linux distributions as "variants" o the GNU seestem, an asks that sic operatin seestems be referred tae as GNU/Linux or a Linux-based GNU system. While some distributions maks a pynt o uisin the soudert form - for ordinar Debian GNU/Linux - its uiss ootwi the enthusiast community is leemitit, an Linus Torvalds haes said that he finds cryin Linux in general GNU/Linux "just ridiculous" [9]. The disteenction atween the Linux kirnel an distributions foondit on it is a soorce o raivelment tae mony newcomers, an the namin bides controversial.

[edit] SCO litigation

Main airticle: SCO-Linux controversies

In Mairch 2003, the SCO Group pit in a lawsuit agin IBM, thrapin that IBM haed contributit pairts o SCO's copyrichtit code tae the Linux kirnel in veeolation o IBM's leecense tae uise Unix. Mair oot ower, SCO sent letters tae a wheen companies wairnin that their uiss o Linux athoot a leecense frae SCO micht be actionable, an threapit in the press that they wad be lawin indiveedual Linux uiser. This controversy haes involved lawsuits by SCO agin DaimlerChrysler (dismissed in 2004), an AutoZone, an by Red Hat an ithers agin SCO. Furthermair, whither SCO e'en awns the relevant Unix copyrichts is currently disputit by Novell.

As per the Utah District Coort rulin on Juilie 3rd, 2006; 182 claims oot o 294 claims made by SCO agin IBM haes been dismissed.[10]

SCO's threaps haes varied widely. As of 2006, nae pruif o SCO's claims o copied code in Linux haes been providit.

[edit] Development

More Than a Gigabuck: Estimating GNU/Linux's Size, a 2001 study of Red Hat Linux 7.1, found that this distribution contained 30 million source lines of code.[11] 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 1.08 billion dollars (year 2000 U.S. dollars) to develop in the United States.

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

In a later study, Counting potatoes: The size of Debian 2.2, the same analysis was performed for Debian GNU/Linux version 2.2.[12] This distribution contained over fifty-five million source lines of code, and the study estimated that it would have cost 1.9 billion dollars (year 2000 U.S. dollars) to develop by conventional means.

[edit] Applications

A KDE desktop on the SUSE distribution.
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A KDE desktop on the SUSE distribution.

Linux has historically been used mainly as a server operating system, but its low cost, flexibility, and Unix background make it suitable for a wide range of applications. Linux is 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.

Due to its low cost and its high configurability, Linux is often used in embedded systems such as television set-top boxes, mobile phones, and handheld devices. Linux has become a major competitor to the proprietary Symbian OS found in many mobile phones, and it is an alternative to the dominant Windows CE and Palm OS operating systems on handheld devices. The popular TiVo digital video recorder uses a customized version of Linux. Several network firewall and router standalone products, including several from Linksys, use Linux internally, using its advanced firewalling and routing capabilities.

Linux is increasingly common as an operating system for supercomputers. In the November 2005 TOP500 list of supercomputers, the two fastest supercomputers in the world ran Linux. Of the 500 systems, 371 (74.2%) ran some version of Linux, including seven of the top ten.

The Sony PlayStation 3 video game console, scheduled to be released in November 2006, will run Linux by default. Sony has previously released a PS2 Linux do-it-yourself kit for their PlayStation 2 video game console. Game developers like Atari and id Software have released titles to the Linux desktop. Linux Game Publishing also produces games for Linux, licensing and porting them from their Windows source code.

The One Laptop Per Child project, which aims to provide computing devices to all children in developing nations, uses Linux as the devices' operating system.

[edit] Distributions

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Linux is predominantly used as part of a Linux distribution (commonly called a "distro"). These are compiled by individuals, loose-knit teams, and commercial and volunteer organizations. They commonly include additional system and application software, an installer system to ease initial system setup, and integrated management of software installation and upgrading. Distributions are created for many different purposes, including computer architecture support, localization to a specific region or language, real-time applications, and embedded systems, and many 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.[13]

A typical general-purpose distribution includes the Linux kernel, some GNU libraries and tools, command-line shells, the graphical X Window System and an accompanying desktop environment such as KDE or GNOME, together with thousands of application software packages, from office suites to compilers, text editors, and scientific tools.

[edit] Desktop usage

A GNOME desktop running from the GNOME LiveCD.
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A GNOME desktop running from the GNOME LiveCD.

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The high level of access granted to Linux's internals has led to Linux users traditionally tending to be more technologically oriented than users of Microsoft Windows and Mac OS, sometimes revelling in the tag of "hacker" or "geek". Linux and other free software projects have been frequently criticized for not going far enough to ensure ease of use.Template:Cn

This stereotype has begun to be dispelled in recent years. Linux may now be used with a user interface that is very similar to those running on other operating systems. Users may have to switch application software, and there are often fewer "known" options (as in the case of computer games) but there exist replacements for all general-purpose software, and general applications like spreadsheets, word processors, and browsers are available for Linux in profusion. Additionally, a growing number of proprietary software vendors are supporting Linux,[14] and compatibility layers such as the Wine system allow some Windows application software and drivers to be used on Linux without requiring the vendor to adapt them.

Linux's roots in the Unix operating system mean that in addition to graphical configuration tools and control panels available for many system settings and services, plain-text configuration files are still commonly used to configure the OS and can readily be made accesible (or not) to users, at the administrator's will.

The Berlin-based organization Relevantive concluded in 2003 that the usability of Linux for a set of desktop-related tasks was "nearly equal to Windows XP."[15] Since then, there have been numerous independent studies and articles which indicate that a modern Linux desktop using either GNOME or KDE is on par with Microsoft Windows in a business setting.[16]

[edit] Market share and uptake

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According to the market research company IDC, 25% of servers and 2.8% of desktop computers ran Linux as of 2004.[17] Proponents and analysts attribute the success of Linux to its security, reliability,[18] low cost, and freedom from vendor lock-in,[19]. The frictional cost of switching and lack of support for some hardware and many application programs designed for Windows, especially games or uncommon business software, are two important factors inhibiting adoption.

The Linux market is rapidly growing and the revenue of servers, desktops, and packaged software running Linux is expected to exceed $35.7 billion by 2008.[20] The actual installed user base may be higher than indicated by this figure, as most Linux distributions and applications are freely available and redistributable.

The paper Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers![21] identifies many quantitative studies of open source software, on topics including market share and reliability, with many studies specifically examining Linux.

[edit] Installation

The most common method of installing Linux on a personal computer is by booting from a CD-ROM that contains the installation program and installable software. Such a CD can be burned from a downloaded ISO image, purchased alone for a low price, can be obtained as part of a box set that may also include manuals and additional commercial software and in a few cases shipped for free by request. Mini CD images allow Linux to be installed from a disk with a small form factor.

As with servers, personal computers that come with Linux already installed are available from vendors including Hewlett-Packard and Dell, although generally only for their business desktop line.

Alternatives to traditional desktop installation include thin client installation, where the operating system is loaded and run from a centralised machine over a network connection; and running from a Live CD, where the computer boots the entire operating system from CD without first installing it on the computer's hard disk.

On embedded devices, Linux is typically held in the device's firmware and may or may not be consumer-accessible.

[edit] Programming on Linux

The GNU Compiler Collection (GCC) is the standard compiler family for most Linux systems. Amongst others, GCC provides frontends for C, C++ and Java. Most distributions come installed with interpreters for Perl, Python and other scripting languages, and several now include C# via the Mono project.

There are a number of Integrated development environments available including KDevelop, Anjuta, NetBeans, and Eclipse while the traditional editors Emacs and Vim remain popular.Template:Cn

The two main widget toolkits used for contemporary GUI programming are Qt and the Gimp Toolkit, known as GTK+.

As well as these free and open source options, there are proprietary compilers and tools available from a range of companies such as Intel,[22] PathScale[23] and the Portland Group.[24]

[edit] Support

Technical support is provided by commercial suppliers and by other Linux users, usually in online forums, IRC, newsgroups, and mailing lists. Linux User Groups have traditionally been organized to provide support for Linux in specific cities and regions.

The business model of commercial suppliers is generally dependent on charging for support, especially for business users. A number of companies 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.

[edit] See also

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  • List of Linux distributions
  • Comparison of Linux distributions
  • The Cathedral and the Bazaar
  • Total cost of ownership
  • One page Linux reference

[edit] References

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  1. http://news.netcraft.com/archives/2006/10/07/rackspace_most_reliable_hoster_in_september.html
  2. Template:Cite news
  3. Torvalds, Linux. "What would you like to see most in minix?". Usenet: comp.os.minix. Retrieved 2006-09-09 from [1]
  4. 4.0 4.1 Torvalds, Linus. "How to pronounce "Linux"?". Usenet: comp.os.linux. Retrieved 2006-08-08 from [2]
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  22. http://www.intel.com/cd/software/products/asmo-na/eng/linux/index.htm
  23. http://www.pathscale.com/ekopath.html
  24. http://www.pgroup.com/

[edit] External links

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  • Linux Online — distributions and FTP sites (sortable by categories).
  • DistroWatch.com — distribution information and announcements.

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