GNU ( ) is an extensive collection of

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

(394 packages ), which can be used as an

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

. Most of GNU is licensed under the

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

's own General Public License ( GPL). GNU is also the project within which the

concept originated.

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

, the founder of the project, views GNU as a "technical means to a social end". Relatedly,

Lawrence Lessig Lester Lawrence "Larry" Lessig III (born June 3, 1961) is an American legal scholar and political activist. He is the Roy L. Furman Professor of Law at Harvard Law School and the former director of the Edmond J. Safra Center for Ethics at Harvar ...

states in his introduction to the second edition of Stallman's book '' Free Software, Free Society'' that in it Stallman has written about "the social aspects of software and how Free Software can create community and social justice".

Name

''GNU'' is a recursive acronym for "GNU's Not Unix!", chosen because GNU's design is

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

, but differs from

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

by being free software and containing no Unix code. Stallman chose the name by using various plays on words, including the song " The Gnu".

History

Development of the GNU software was initiated by

while he worked at the MIT Artificial Intelligence Laboratory. It was called the GNU Project, and was publicly announced on September 27, 1983, on the net.unix-wizards and net.usoft

newsgroup A Usenet newsgroup is a repository usually within the Usenet system for messages posted from users in different locations using the Internet. They are not only discussion groups or conversations, but also a repository to publish articles, start ...

s by Stallman. Software development began on January 5, 1984, when Stallman quit his job at the Lab so that they could not claim ownership or interfere with distributing GNU components as free software. The goal was to bring a completely free software operating system into existence. Stallman wanted computer users to be free to study the source code of the software they use, share software with other people, modify the behavior of software, and publish their modified versions of the software. This philosophy was published as the

GNU Manifesto __NOTOC__ The ''GNU Manifesto'' is a direct action, call-to-action by Richard Stallman encouraging participation and support of the GNU Project's goal in developing the GNU free software, free computer operating system. The GNU Manifesto was publ ...

in March 1985. Richard Stallman's experience with the Incompatible Timesharing System (ITS), an early operating system written in

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

that became obsolete due to discontinuation of

PDP-10 Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, especi ...

, the computer architecture for which ITS was written, led to a decision that a portable system was necessary. It was thus decided that the development would be started using C and

Lisp Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized Polish notation#Explanation, prefix notation. Originally specified in the late 1950s, ...

as system programming languages, and that GNU would be compatible with Unix. At the time, Unix was already a popular proprietary operating system. The design of Unix was modular, so it could be reimplemented piece by piece. Much of the needed software had to be written from scratch, but existing compatible third-party free software components were also used such as the

TeX Tex, TeX, TEX, may refer to: People and fictional characters * Tex (nickname), a list of people and fictional characters with the nickname * Tex Earnhardt (1930–2020), U.S. businessman * Joe Tex (1933–1982), stage name of American soul singer ...

typesetting system, the

X Window System The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X originated as part of Project Athena at Massachusetts Institute of Technology (MIT) in 1984. The X protocol has been at ...

, and the

Mach The Mach number (M or Ma), often only Mach, (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a Boundary (thermodynamic), boundary to the local speed of sound. It is named after the Austrian physi ...

microkernel that forms the basis of the GNU Mach core of GNU Hurd (the official kernel of GNU). With the exception of the aforementioned third-party components, most of GNU has been written by volunteers; some in their spare time, some paid by companies, educational institutions, and other non-profit organizations. In October 1985, Stallman set up the

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

(FSF). In the late 1980s and 1990s, the FSF hired software developers to write the software needed for GNU. As GNU gained prominence, interested businesses began contributing to development or selling GNU software and technical support. The most prominent and successful of these was Cygnus Solutions, now part of

Red Hat Red Hat, Inc. (formerly Red Hat Software, Inc.) is an American software company that provides open source software products to enterprises and is a subsidiary of IBM. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North ...

Components

The system's basic components include the

GNU Compiler Collection The GNU Compiler Collection (GCC) is a collection of compilers from the GNU Project that support various programming languages, Computer architecture, hardware architectures, and operating systems. The Free Software Foundation (FSF) distributes ...

(GCC), the GNU C library (glibc), and

GNU Core Utilities The GNU Core Utilities or coreutils is a collection of GNU software that implements many standard, Unix-based shell commands. The utilities generally provide POSIX compliant interface when the environment variable is set, but otherwise offers ...

(coreutils), but also the GNU Debugger (GDB), GNU Binary Utilities (binutils), and the GNU Bash shell. GNU developers have contributed to Linux

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manch ...

s of GNU applications and utilities, which are now also widely used on other operating systems such as

BSD The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

variants, Solaris and

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

. Many GNU programs have been ported to other operating systems, including proprietary platforms such as

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

and macOS. GNU programs have been shown to be more reliable than their proprietary Unix counterparts. , there are a total of 467 GNU packages (including decommissioned, 394 excluding) hosted on the official GNU development site.

GNU as an operating system

In its original meaning, and one still common in hardware engineering, the operating system is a basic set of functions to control the hardware and manage things like

task scheduling In computing, scheduling is the action of assigning resources to perform tasks. The resources may be processors, network links or expansion cards. The tasks may be threads, processes or data flows. The scheduling activity is carried out by ...

and

system call In computing, a system call (syscall) is the programmatic way in which a computer program requests a service from the operating system on which it is executed. This may include hardware-related services (for example, accessing a hard disk drive ...

s. In modern terminology used by software developers, the collection of these functions is usually referred to as a kernel, while an 'operating system' is expected to have a more extensive set of programs. The GNU project maintains two kernels itself, allowing the creation of pure GNU operating systems, but the GNU toolchain is also used with non-GNU kernels. Due to the two different definitions of the term 'operating system', there is an ongoing debate concerning the naming of distributions of GNU packages with a non-GNU kernel. (See below.)

With kernels maintained by GNU and FSF

GNU Hurd

The original kernel of GNU Project is the GNU Hurd (together with the GNU Mach microkernel), which was the original focus of the

(FSF).Vaughan-Nichols, Steven J.
Opinion: The top 10 operating system stinkers
, ''

Computerworld ''Computerworld'' (abbreviated as CW) is a computer magazine published since 1967 aimed at information technology (IT) and Business computing, business technology professionals. Original a print magazine, ''Computerworld'' published its final pr ...

'', April 9, 2009: "... after more than 25 years in development, GNU remains incomplete: its kernel, Hurd, has never really made it out of the starting blocks. ... Almost no one has actually been able to use the OS; it's really more a set of ideas than an operating system." With the April 30, 2015 release of the Debian GNU/Hurd 2015 distro, GNU now provides all required components to assemble an operating system that users can install and use on a computer. However, the Hurd kernel is not yet considered production-ready but rather a base for further development and non-critical application usage.

Linux-libre

In 2012, a fork of the

Linux kernel The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

became officially part of the GNU Project in the form of

Linux-libre According to the Free_Software_Foundation_Latin_America , Free Software Foundation Latin America, Linux-libre is a modified version of the Linux kernel that contains no binary blobs, Obfuscation (software), obfuscated code, or code released u ...

, a variant of Linux with all proprietary components removed. The GNU Project has endorsed Linux-libre distributions, such as Trisquel,

Parabola GNU/Linux-libre Parabola GNU/Linux-libre is a Free and open-source software, free and open-source Linux distribution based on Arch Linux and Arch Linux ARM for the x86-64, i686, and ARMv7 architectures. It is distinguished from other Arch-based distributions b ...

, PureOS and GNU Guix System.

With non-GNU kernels

Because of the development status of Hurd, GNU is usually paired with other kernels such as

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

. Whether the combination of GNU libraries with external kernels is a GNU operating system with a kernel (e.g. GNU with Linux), because the GNU collection renders the kernel into a usable operating system as understood in modern software development, or whether the kernel is an operating system unto itself with a GNU layer on top (i.e. Linux with GNU), because the kernel can operate a machine without GNU, is a matter of ongoing debate. The FSF maintains that an operating system built using the

and GNU tools and utilities should be considered a variant of GNU, and promotes the term ''GNU/Linux'' for such systems (leading to the

GNU/Linux naming controversy Since the 1990s, there has been an ongoing debate whether computer operating systems that use GNU software and the Linux kernel should be referred to as "GNU/Linux" or "Linux" systems. Proponents of the term ''Linux'' argue that it is far mor ...

). This view is not exclusive to the FSF. Notably,

Debian Debian () is a free and open-source software, free and open source Linux distribution, developed by the Debian Project, which was established by Ian Murdock in August 1993. Debian is one of the oldest operating systems based on the Linux kerne ...

, one of the biggest and oldest Linux distributions, refers to itself as ''Debian GNU/Linux''.

Copyright, GNU licenses, and stewardship

The GNU Project recommends that contributors assign the copyright for GNU packages to the Free Software Foundation, though the Free Software Foundation considers it acceptable to release small changes to an existing project to the

public domain The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds ...

. However, this is not required; package maintainers may retain copyright to the GNU packages they maintain, though since only the copyright holder may enforce the license used (such as the GNU GPL), the copyright holder in this case enforces it rather than the Free Software Foundation. For the development of needed software, Stallman wrote a license called the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

(first called Emacs General Public License), with the goal to guarantee users freedom to share and change free software. Stallman wrote this license after his experience with

James Gosling James Arthur Gosling (born 19 May 1955) is a Canadian computer scientist, best known as the founder and lead designer behind the Java (programming language), Java programming language. Gosling was elected a member of the National Academy of E ...

and a program called UniPress, over a controversy around software code use in the

GNU Emacs GNU Emacs is a text editor and suite of free software tools. Its development began in 1984 by GNU Project founder Richard Stallman, based on the Emacs editor developed for Unix operating systems. GNU Emacs has been a central component of the GNU ...

program. For most of the 80s, each GNU package had its own license: the Emacs General Public License, the GCC General Public License, etc. In 1989, FSF published a single license they could use for all their software, and which could be used by non-GNU projects: the

(GPL). This license is now used by most of GNU software, as well as a large number of free software programs that are not part of the GNU Project; it also historically has been the most commonly used

free software license A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder (usually the author) ...

(though recently challenged by the

MIT license The MIT License is a permissive software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts very few restrictions on reuse and therefore has high license compatibility. Unl ...

). It gives all recipients of a program the right to run, copy, modify and distribute it, while forbidding them from imposing further restrictions on any copies they distribute. This idea is often referred to as

copyleft Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, ''freedoms'' refers to the use of the work for any purpose, ...

. In 1991, the

GNU Lesser General Public License The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own ...

(LGPL), then known as the Library General Public License, was written for the GNU C Library to allow it to be linked with proprietary software. 1991 also saw the release of version 2 of the GNU GPL. The GNU Free Documentation License (FDL), for documentation, followed in 2000. The GPL and LGPL were revised to version 3 in 2007, adding clauses to protect users against hardware restrictions that prevent users from running modified software on their own devices. Besides GNU's packages, the GNU Project's licenses can and are used by many unrelated projects, such as the

, often used with GNU software. A majority of free software such as the X Window System, is licensed under permissive free software licenses.

Logo

The logo for GNU is a gnu head. Originally drawn by Etienne Suvasa, a bolder and simpler version designed by Aurelio Heckert is now preferred. It appears in GNU software and in printed and electronic documentation for the GNU Project, and is also used in Free Software Foundation materials.

There was also a modified version of the official logo. It was created by the

in September 2013 in order to commemorate the 30th anniversary of the

References

External links

*
Ports of GNU utilities for Microsoft Windows

The daemon, the GNU and the penguin
{{Authority control Free software operating systems GNU Project Mach (kernel) Microkernel-based operating systems Unix variants Computing acronyms