The GNU/Linux operating system is free software created to replace the Unix operating system. The system aims towards POSIX compliance, though it is not officially compliant and therefore cannot bear the trademark "UNIX." The GNU project was started by atheist programmer Richard Stallman and was the impetus behind the creation of the Free Software Foundation. Except for the small but essential kernel (called Linux after its creator Linus Torvalds), substantial components of the operating system code were created by Stallman and other FSF contributors. There's a dispute over whether the FSF should be credited when mentioning the use of Linux. The trade press refer to the overall system as "Linux", which annoys Stallman to no end. Essays on the FSF website promote the use of the term "GNU/Linux" when referring to a system with Linux kernel and GNU project core components.
The Linux kernel communicates with the hardware and provides for many complex and essential operations such as process scheduling, memory management and file system operation. This is required to support the needs of all applications run on the system (such as the graphical user interface, media players, and servers). Most of these applications are not part of the Linux kernel project, and are part of separate projects, including GNU, but those who are unaware of or not concerned about the history of the project commonly used "Linux" to refer to the whole operating system. The Linux kernel was initially developed by Finnish grad student Linus Torvalds as an experimental project to run a UNIX-like system on x86-based PC hardware.
At this point, a very substantial portion of the software commonly used on a desktop system are not GNU software projects, such as KDE (graphical desktop environment), Firefox, OpenOffice.org, and Python (high-level programming language). On the other hand, even these popular products rely on basic services provided by GNU, such as the C runtime library (libc), compiler framework (gcc), and core POSIX command line utilities. Additionally, the GNU project includes several more substantial applications, such as the graphical desktop environment GNOME, which compete heavily with their alternatives.
GNU/Linux distinguishes itself from other operating systems such as proprietary UNIX and Microsoft Windows in that the source code for a complete working system is distributed under various open source licenses. In essence, this means that anybody can modify the code to their needs, and that the development most components happens in an open community, rather than in a closed commercial environment. Any improvements to the code will be contributed to the community, and any software that is based upon viral licenses will be, in turn, licenses under these. The Linux kernel itself is licensed under the GNU General Public License (GPL).
GNU/Linux is also different to the closed source operating system vendors in that the software is distributed by many different companies. Major GNU/Linux distributions include Red Hat, SUSE, Debian and Ubuntu. There are literally hundreds of GNU/Linux distributions as can be seen on DistroWatch.com.
Numerous sources , including Steve Ballmer, one of the driving minds behind the success of Microsoft, have claimed that the Open Source movement is inherently Communist. Both Free Software and Communism shun the idea of personal property, instead favoring a communal ownership where no single entity has control or authority.
In 2005 Forbes.com posted an article estimating Linux ran 60% of the world's top supercomputers at that time. In 2003 the IBM GNU/Linux Technology Center concluded that GNU/Linux has enterprise class reliability. GNU/Linux servers can run without reboot for years as can usually be seen at the Longest uptimes URL on Netcraft.com. Another location to check on Linux uptime statistics is the Machine uptimes page at Linux Counter.
Owing to the nature of open source software, many variants of a GUN/Linux distribution may be created by using the original code and making changes to it to suit a particular need. For example, there is also a Ubuntu Christian Edition.
GNU/Linux is quite possibly becoming one of the most commonly adopted operating systems in the world. However, this is difficult to quantify with hard evidence since most Linux distributions are given away for "free" and there are few sales records or marketing numbers to review. While personal computers in the United States and other "first world nations" still overwhelmingly use Microsoft operating systems such as Windows XP, GNU/Linux is a common choice for web servers, file servers and embedded platforms, thanks to its perceived reliability, low/no cost, and the fact that modifications to the source code can readily be made by anyone. For example, Linux has seen widespread use in numerous mass produced consumer electronic devices such as broadband residential routers, Digital Video Recorders, and cellphones.
As an example, in March of 2007 the server hosting the Conservapedia web site was running the GNU/Linux operating system
Linux as the 'Best of the Public'
The ongoing development of the GNU/Linux operating system represents perhaps the single most important example of the 'best of the public' collaboration model in the field of technology. The excellent stability and security of GNU/Linux, both in server and consumer versions, provide a powerful example of the success of this model.
From its inception, it has been difficult to find new computers outside of the server and market available with GNU/Linux pre-installed. Although specialty companies like System76 and Zareason do sell computers equipped with desktop versions of Linux (specifically Ubuntu), until recently, mainstream computer manufacturers like Dell and HP resisted this trend. Users typically need to download the GNU/Linux distribution of their choice and install it on a computer themselves. Because many home computer users find the installation of an operating system a difficult task, this added step hinders the increase in the number of computers using a desktop version of Linux. This situation drastically changed in 2007 when Dell started selling laptop and desktop computers to the general public with Linux pre-installed.
During 2008, a new type of low cost laptop computer, the "netbook" was introduced by most of the major manufacturers. To keep costs down, Linux was offered on most of the lines as an alternative to Windows XP (Windows Vista being unable to run on the low powered computers), bringing GNU/Linux into the mainstream computer market for the first time.
Misconceptions about GNU/Linux
GNU/Linux is in often referred to as GNU/Linux, because Linux is not an operating system unto itself, but rather another free component of a fully functioning GNU system made useful by the GNU corelibraries, shell utilities and vital system components comprising a full Operating System as defined by POSIX. Many computer users run a modified version of the GNU system every day, without realizing it. Through a peculiar turn of events, the version of GNU which is widely used today is often called "Linux", and many of its users are not aware that it is basically the GNU system, developed by the GNU Project. There really is a Linux, and these people are using it, but it is just a part of the system they use. Linux is actually the kernel, a minuscule program in the operating system that allocates the machine's resources to the other programs that you run. The kernel is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Linux is normally used in combination with the GNU operating system: the whole system is basically GNU with Linux added, or GNU/Linux. Therefore, the so-called "Linux" distributions are really distributions of GNU/Linux.