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65-481: It is built on Linux and provides a distributed software architecture that moves many operating system responsibilities out of the IOS process and has a copy of IOS running as a separate process. Since it runs a copy of IOS, all CLI commands are the same between Cisco IOS and IOS XE, in contrast to IOS XR , which has a completely different code base and whose developers implemented a different CLI command set. IOS XE

130-472: A high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, AT&T licensed the operating system's source code as a trade secret to anyone who asked. As a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of its regional operating companies , and

195-424: A minimalist functionality, while more elaborate window managers such as FVWM , Enlightenment , or Window Maker provide more features such as a built-in taskbar and themes , but are still lightweight when compared to desktop environments. Desktop environments include window managers as part of their standard installations, such as Mutter (GNOME), KWin (KDE), or Xfwm (xfce), although users may choose to use

260-516: A solution stack such as LAMP . The source code of Linux may be used, modified, and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the GNU General Public License (GPL). The license means creating novel distributions is permitted by anyone and is easier than it would be for an operating system such as MacOS or Microsoft Windows . The Linux kernel, for example,

325-471: A character in The Demonata series of books Brigitte Kernel (born 1959), French journalist and writer See also [ edit ] Colonel , a senior military officer rank that is pronounced "kernel" Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Kernel . If an internal link led you here, you may wish to change

390-470: A competing OS, agrees that "Linux wasn't designed, it evolved", but considers this to be a limitation, proposing that some features, especially those related to security, cannot be evolved into, "this is not a biological system at the end of the day, it's a software system." A Linux-based system is a modular Unix-like operating system, deriving much of its basic design from principles established in Unix during

455-974: A different window manager if preferred. Wayland is a display server protocol intended as a replacement for the X11 protocol; as of 2022 , it has received relatively wide adoption. Unlike X11, Wayland does not need an external window manager and compositing manager. Therefore, a Wayland compositor takes the role of the display server, window manager, and compositing manager. Weston is the reference implementation of Wayland, while GNOME's Mutter and KDE's KWin are being ported to Wayland as standalone display servers. Enlightenment has already been successfully ported since version 19. Additionally, many window managers have been made for Wayland, such as Sway or Hyprland, as well as other graphical utilities such as Waybar or Rofi. Linux currently has two modern kernel-userspace APIs for handling video input devices: V4L2 API for video streams and radio, and DVB API for digital TV reception. Due to

520-539: A lot of the same code, IOS XR is a completely different code base. Since IOS XE has IOSd running as an application on top of Linux, it becomes possible to also run different applications on the hardware, a good example of this is running Wireshark on a switch. Another example is the Cisco IOS XE Open Service Containers. Linux This is an accepted version of this page Linux ( / ˈ l ɪ n ʊ k s / , LIN -uuks )

585-404: A place in server installations such as the popular LAMP application stack. The use of Linux distributions in home and enterprise desktops has been growing. Linux distributions have also become popular in the netbook market, with many devices shipping with customized Linux distributions installed, and Google releasing their own ChromeOS designed for netbooks. Linux's greatest success in

650-502: A popular CLI shell. The graphical user interface (or GUI) used by most Linux systems is built on top of an implementation of the X Window System . More recently, the Linux community has sought to advance to Wayland as the new display server protocol, in place of X11. Many other open-source software projects contribute to Linux systems. Installed components of a Linux system include the following: The user interface , also known as

715-481: A significant 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

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780-493: 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 to sell hardware. This used to be the norm in the computer industry, with operating systems such as CP/M , Apple DOS , and versions of the classic Mac OS before 7.6 freely copyable (but not modifiable). As computer hardware standardized throughout

845-524: A stochastic process Transition kernel , a generalization of a stochastic kernel Pricing kernel , the stochastic discount factor used in mathematical finance Positive-definite kernel , a generalization of a positive-definite matrix Kernel trick , in statistics Reproducing kernel Hilbert space Science [ edit ] Seed , inside the nut of most plants or the fruitstone of drupes, especially: Apricot kernel Corn kernel Palm kernel Wheat kernel Atomic nucleus ,

910-972: A system's software from one central location. 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 , and SUSE does with openSUSE . In many cities and regions, local associations known as Linux User 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 of support, with notable examples being Unix & Linux Stack Exchange , LinuxQuestions.org and

975-475: A technique for designing efficient algorithms Kernel, a routine that is executed in a vectorized loop, for example in general-purpose computing on graphics processing units KERNAL , the Commodore operating system Mathematics [ edit ] Objects [ edit ] Kernel (algebra) , a general concept that includes: Kernel (linear algebra) or null space, a set of vectors mapped to

1040-402: A user may interact with the application; however, certain extensions of the X Window System are not capable of working over the network. Several X display servers exist, with the reference implementation, X.Org Server , being the most popular. Server distributions might provide a command-line interface for developers and administrators, but provide a custom interface for end-users, designed for

1105-453: 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. Many developers of open-source software agree that the Linux kernel was not designed but rather evolved through natural selection . Torvalds considers that although

1170-554: Is a family of open-source Unix-like operating systems based on the Linux kernel , an operating system kernel first released on September 17, 1991, by Linus Torvalds . Linux is typically packaged as a Linux distribution (distro), which includes the kernel and supporting system software and libraries — many of which are provided by the GNU Project — to create a complete operating system. Many Linux distributions use

1235-569: Is licensed under the GPLv2, with an exception for system calls that allows code that calls the kernel via system calls not to be licensed under the GPL. Because of the dominance of Linux-based Android on smartphones , Linux, including Android, has the largest installed base of all general-purpose operating systems as of May 2022 . Linux is, as of March 2024 , used by around 4 percent of desktop computers . The Chromebook , which runs

1300-508: Is released separately for ASR 1000 and Catalyst 3850. Cisco IOS is a monolithic operating system running directly on the hardware while IOS XE is a combination of a Linux kernel and a monolithic application (IOSd) that runs on top of this kernel. On the other hand, IOS XR is based on QNX (since version 5.0 it's also based on Linux), where the IOSd application has been separated into many different applications. While IOS XE (IOSd) and IOS share

1365-403: 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,

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1430-594: Is the Bourne-Again Shell (bash), originally developed for the GNU Project, other shells such as Zsh are also used. Most low-level Linux components, including various parts of the userland , use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks and provides very simple inter-process communication . On desktop systems, the most popular user interfaces are

1495-475: Is typically built into the firmware and is highly tailored to the system. This includes routers , automation controls, smart home devices , video game consoles , televisions (Samsung and LG smart TVs ), automobiles (Tesla, Audi, Mercedes-Benz, Hyundai, and Toyota), and spacecraft ( Falcon 9 rocket, Dragon crew capsule, and the Ingenuity Mars helicopter). The Unix operating system

1560-415: Is used on a wide variety of devices including PCs, workstations , mainframes and embedded systems . Linux is the predominant operating system for servers and is also used on all of the world's 500 fastest supercomputers . When combined with Android , which is Linux-based and designed for smartphones , they have the largest installed base of all general-purpose operating systems . The Linux kernel

1625-480: Is visible Kernel (statistics) , a weighting function used in kernel density estimation to estimate the probability density function of a random variable Integral kernel or kernel function , a function of two variables that defines an integral transform Heat kernel , the fundamental solution to the heat equation on a specified domain Convolution kernel Stochastic kernel , the transition function of

1690-497: 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 command-line shell , and a windowing system ) were completed, although low-level elements such as device drivers , daemons , and the kernel , called GNU Hurd , were stalled and incomplete. Minix

1755-761: The GNU toolchain , which includes the GNU Compiler Collection (GCC) and the GNU Build System . Amongst others, GCC provides compilers for Ada , C , C++ , Go and Fortran . Many programming languages have a cross-platform reference implementation that supports Linux, for example PHP , Perl , Ruby , Python , Java , Go , Rust and Haskell . First released in 2003, the LLVM project provides an alternative cross-platform open-source compiler for many languages. Proprietary compilers for Linux include

1820-473: The GUI shells , packaged together with extensive Desktop environments , such as KDE Plasma , GNOME , MATE , Cinnamon , LXDE , Pantheon , and Xfce , though a variety of additional user interfaces exist. Most popular user interfaces are based on the X Window System, often simply called "X". It provides network transparency and permits a graphical application running on one system to be displayed on another where

1885-692: The Intel C++ Compiler , Sun Studio , and IBM XL C/C++ Compiler . BASIC is available in procedural form from QB64 , PureBasic , Yabasic , GLBasic , Basic4GL , XBasic , wxBasic , SdlBasic , and Basic-256 , as well as object oriented through Gambas , FreeBASIC , B4X, Basic for Qt , Phoenix Object Basic, NS Basic , ProvideX, Chipmunk Basic , RapidQ and Xojo . Pascal is implemented through GNU Pascal , Free Pascal , and Virtual Pascal , as well as graphically via Lazarus , PascalABC.NET , or Delphi using FireMonkey (previously through Borland Kylix ). Kernel From Misplaced Pages,

1950-476: The shell , is either a command-line interface (CLI), a graphical user interface (GUI), or controls attached to the associated hardware, which is common for embedded systems. For desktop systems, the default user interface is usually graphical, although the CLI is commonly available through terminal emulator windows or on a separate virtual console . CLI shells are text-based user interfaces, which use text for both input and output. The dominant shell used in Linux

2015-399: The 1970s and 1980s. Such a system uses a monolithic kernel , the Linux kernel, which handles process control, networking, access to the peripherals , and file systems . Device drivers are either integrated directly with the kernel or added as modules that are loaded while the system is running. The GNU userland is a key part of most systems based on the Linux kernel, with Android being

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2080-454: The 1980s, it became more difficult for hardware manufacturers to profit from this tactic, as the OS would run on any manufacturer's computer that shared the same architecture. Most programming languages support Linux either directly or through third-party community based ports . The original development tools used for building both Linux applications and operating system programs are found within

2145-674: The GNU General Public License (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 , LSB , 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 through collaboration , are often produced independently of each other. The fact that

2210-464: The Linux kernel, key components that make up a distribution may include a display server (windowing system) , a package manager , a bootloader and the Bash shell . Linux is one of the most prominent examples of free and open-source software collaboration. While originally developed for x86 based personal computers , it has since been ported to more platforms than any other operating system, and

2275-650: The Linux kernel-based ChromeOS , dominates the US K–12 education market and represents nearly 20 percent of sub-$ 300 notebook sales in the US. Linux is the leading operating system on servers (over 96.4% of the top one million web servers' operating systems are Linux), leads other big iron systems such as mainframe computers , and is used on all of the world's 500 fastest supercomputers (as of November 2017 , having gradually displaced all competitors). Linux also runs on embedded systems , i.e., devices whose operating system

2340-613: The Linux kernel. On July 3, 1991, to implement Unix system calls , Linus Torvalds attempted unsuccessfully to obtain a digital copy of the POSIX standards documentation with a request to the comp.os.minix newsgroup . After not finding the POSIX documentation, Torvalds initially resorted to determining system calls from SunOS documentation owned by the university for use in operating its Sun Microsystems server. He also learned some system calls from Tanenbaum's Minix text. Torvalds began

2405-471: The beginning, it was rather casually hacked on by huge numbers of volunteers coordinating only through the Internet. Quality was maintained not by rigid standards or autocracy but by the naively simple strategy of releasing every week and getting feedback from hundreds of users within days, creating a sort of rapid Darwinian selection on the mutations introduced by developers." Bryan Cantrill , an engineer of

2470-486: The center of an atom Companies [ edit ] Kernel (agriculture company) , a Ukrainian producer of sunflower oil Kernel (neurotechnology company) , a developer of neural interfaces The Kernel Brewery , a craft brewery in London The Kernel , an Internet culture website, now part of The Daily Dot Other uses [ edit ] Kernel (EP) , by the band Seam Kernel Fleck ,

2535-447: The complexity and diversity of different devices, and due to the large number of formats and standards handled by those APIs, this infrastructure needs to evolve to better fit other devices. Also, a good userspace device library is the key to the success of having userspace applications to be able to work with all formats supported by those devices. The primary difference between Linux and many other popular contemporary operating systems

2600-498: The consumer market is perhaps the mobile device market, with Android being the dominant operating system on smartphones and very popular on tablets and, more recently, on wearables . Linux gaming is also on the rise with Valve showing its support for Linux and rolling out SteamOS , its own gaming-oriented Linux distribution, which was later implemented in their Steam Deck platform. Linux distributions have also gained popularity with various local and national governments, such as

2665-467: The design of Unix served as a scaffolding, "Linux grew with a lot of mutations – and because the mutations were less than random, they were faster and more directed than alpha-particles in DNA ." Eric S. Raymond considers Linux's revolutionary aspects to be social, not technical: before Linux, complex software was designed carefully by small groups, but "Linux evolved in a completely different way. From nearly

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2730-508: The development of 386BSD , from which NetBSD , OpenBSD and FreeBSD descended, predated that of Linux. Linus Torvalds has stated on separate occasions that if the GNU kernel or 386BSD had been available at the time (1991), he probably would not have created Linux. While attending the University of Helsinki in the fall of 1990, Torvalds enrolled in a Unix course. The course used a MicroVAX minicomputer running Ultrix , and one of

2795-532: The development of the Linux kernel on Minix and applications written for Minix were also used on Linux. Later, Linux matured and further Linux kernel development took place on Linux systems. GNU applications also replaced all Minix components, because it was advantageous to use the freely available code from the GNU Project with the fledgling operating system; code licensed under the GNU GPL can be reused in other computer programs as long as they also are released under

2860-476: The development of the components of the system and free software. An analysis of the Linux kernel in 2017 showed that well over 85% of the code was developed by programmers who are being paid for their work, leaving about 8.2% to unpaid developers and 4.1% unclassified. Some of the major corporations that provide contributions include Intel , Samsung , Google , AMD , Oracle , and Facebook . Several corporations, notably Red Hat, Canonical , and SUSE have built

2925-559: The federal government of Brazil . Linus Torvalds is the lead maintainer for the Linux kernel and guides its development, while Greg Kroah-Hartman is the lead maintainer for the stable branch. Zoë Kooyman is the executive director of 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

2990-471: The first version of the Linux kernel on the Internet . Like GNU and 386BSD, Linux did not have any Unix code and therefore avoided any current legal issues . Desktop Linux distributions include a windowing system such as X11 or Wayland and a desktop environment such as GNOME , KDE Plasma or Xfce . Distributions intended for servers may not have a graphical user interface at all or include

3055-519: The 💕 [REDACTED] Look up kernel in Wiktionary, the free dictionary. Kernel may refer to: Computing [ edit ] Kernel (operating system) , the central component of most operating systems Kernel (image processing) , a matrix used for image convolution Compute kernel , in GPGPU programming Kernel method , in machine learning Kernelization ,

3120-516: The mid-1990s in the supercomputing community, where organizations such as NASA started to replace their increasingly expensive machines with clusters of inexpensive commodity computers running Linux. Commercial use began when Dell and IBM , followed by Hewlett-Packard , started offering Linux support to escape Microsoft 's monopoly in the desktop operating system market. Today, Linux systems are used throughout computing, from embedded systems to virtually all supercomputers , and have secured

3185-441: The notable exception. The GNU C library , an implementation of the C standard library , works as a wrapper for the system calls of the Linux kernel necessary to the kernel-userspace interface, the toolchain is a broad collection of programming tools vital to Linux development (including the compilers used to build the Linux kernel itself), and the coreutils implement many basic Unix tools . The GNU Project also develops Bash ,

3250-501: The operating system to their specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. 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. Distributions typically use a package manager such as apt , yum , zypper , pacman or portage to install, remove, and update all of

3315-455: The required texts was Operating Systems: Design and Implementation by Andrew S. Tanenbaum . This textbook included a copy of Tanenbaum's Minix operating system. It was with this course that Torvalds first became exposed to Unix. In 1991, he became curious about operating systems. Frustrated by the licensing of Minix, which at the time limited it to educational use only, he began to work on his operating system kernel, which eventually became

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3380-412: The same or a compatible license. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL. Developers worked to integrate GNU components with the Linux kernel, creating a fully functional and free operating system. Linus Torvalds had wanted to call his invention " Freax ", a portmanteau of "free", "freak", and "x" (as an allusion to Unix). During

3445-441: 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. Many Linux distributions manage a remote collection of system software and application software packages available for download and installation through a network connection. This allows users to adapt

3510-586: The start of his work on the system, some of the project's makefiles included the name "Freax" for about half a year. Initially, Torvalds considered the name "Linux" but dismissed it as too egotistical. To facilitate development, the files were uploaded to the FTP server ( ftp.funet.fi ) of FUNET in September 1991. Ari Lemmke, Torvalds' coworker at the Helsinki University of Technology (HUT) who

3575-471: The use case of the system. This custom interface is accessed through a client that resides on another system, not necessarily Linux-based. Several types of window managers exist for X11, including tiling , dynamic , stacking , and compositing . Window managers provide means to control the placement and appearance of individual application windows, and interact with the X Window System. Simpler X window managers such as dwm , ratpoison , or i3wm provide

3640-559: The various distribution-specific support and community forums, such as ones for Ubuntu , Fedora, Arch Linux , Gentoo , etc. 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 bundle cover disks that carry software or even complete Linux distributions. Although Linux distributions are generally available without charge, several large corporations sell, support, and contribute to

3705-511: The word "Linux" in their name, but the Free Software Foundation uses and recommends the name " GNU/Linux " to emphasize the use and importance of GNU software in many distributions, causing some controversy . Thousands of distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian , Fedora Linux , Arch Linux , and Ubuntu , while commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise . Other than

3770-429: The word "Linux" should be pronounced, he included an audio guide with the kernel source code. However, in this recording, he pronounces Linux as /ˈlinʊks/ ( LEEN -uuks ) with a short but close front unrounded vowel , instead of a near-close near-front unrounded vowel as in his newsgroup post. The adoption of Linux in production environments, rather than being used only by hobbyists, started to take off first in

3835-405: The zero vector Kernel (category theory) , a generalization of the kernel of a homomorphism Kernel (set theory) , an equivalence relation: partition by image under a function Difference kernel , a binary equalizer: the kernel of the difference of two functions Functions [ edit ] Kernel (geometry) , the set of points within a polygon from which the whole polygon boundary

3900-508: Was conceived and implemented in 1969, at AT&T 's Bell Labs , in the United States by Ken Thompson , Dennis Ritchie , Douglas McIlroy , and Joe Ossanna . First released in 1971, Unix was written entirely in assembly language , as was common practice at the time. In 1973, in a key pioneering approach, it was rewritten in the C programming language by Dennis Ritchie (except for some hardware and I/O routines). The availability of

3965-498: Was created by Andrew S. Tanenbaum , a computer science professor, and released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn operating system principles. Although the complete source code of Minix was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000. Although not released until 1992, due to legal complications ,

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4030-510: Was designed by Linus Torvalds , following the lack of a working kernel for GNU , a Unix -compatible operating system made entirely of free software that had been undergoing development since 1983 by Richard Stallman . While a separate working Unix-compatible system called Minix was later released, its license was not entirely free at the time. The first entirely free Unix for personal computers, 386BSD , did not appear until 1992, by which time Torvalds had already built and publicly released

4095-459: Was later originally developed, it represented the first successful commercial attempt at distributing a primarily single-user microcomputer that ran a Unix operating system. With Unix increasingly "locked in" as a proprietary product, 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 started

4160-513: Was one of the volunteer administrators for the FTP server at the time, did not think that "Freax" was a good name, so he named the project "Linux" on the server without consulting Torvalds. Later, however, Torvalds consented to "Linux". According to a newsgroup post by Torvalds, the word "Linux" should be pronounced ( / ˈ l ɪ n ʊ k s / LIN -uuks ) with a short 'i' as in 'print' and 'u' as in 'put'. To further demonstrate how

4225-518: Was released from its obligation not to enter the computer business; freed of that obligation, Bell Labs began selling Unix as a proprietary product, where users were not legally allowed to modify it. Onyx Systems began selling early microcomputer-based Unix workstations in 1980. Later, Sun Microsystems , founded as a spin-off of a student project at Stanford University , also began selling Unix-based desktop workstations in 1982. While Sun workstations did not use commodity PC hardware, for which Linux

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