A Linux distribution (also called GNU/Linux distribution by some vendors and users) is a member of the family of Unix-like software distributions built on top of the Linux kernel. Such distributions (often called distros for short) consist of a large collection of software applications such as word processors, spreadsheets, media players and database applications. The operating system will consist of the Linux kernel and, usually, a set of libraries and utilities from the GNU project, with graphics support from the X Window System. Distributions optimized for size may not contain X, and tend to use more compact alternatives to the GNU utilities such as busybox, uclibc or dietlibc. There are currently over three hundred Linux distributions. Most of those are in active development, constantly being revised and improved.

Because most of the kernel and supporting packages are some combination of free software and open source, Linux distributions have taken a wide variety of forms — from fully featured desktop and server operating systems to minimal environments (typically for use in embedded systems, or for booting from a floppy disk). Aside from certain custom software (such as installers and configuration tools) a distribution simply refers to a particular assortment of applications installed on top of a set of libraries married with a version of the kernel, such that its "out-of-the-box" capabilities meets most of the needs of its particular end-user base.

One can distinguish between commercially backed distributions, such as Fedora (Red Hat), openSUSE (Novell), Ubuntu (Canonical Ltd.), and Mandriva Linux and community distributions such as Debian and Gentoo, though there are other distributions that are driven neither by a corporation nor a community; perhaps most famously, Slackware.

History

Before the first Linux distributions, a would-be Linux user was required to be something of a Unix expert, not only knowing what libraries and executables were needed to successfully get the system to boot and run, but also important details concerning configuration and placement of files in the system.Fact: date=May 2008

Linux distributions began to appear very soon after the Linux kernel was first used by individuals outside the original Linux programmers. They were more interested in developing the operating system than they were in application programs, the user interface, or convenient packaging.Fact: date=May 2008

Early distributions included:

• H J Lu's "Boot-root" a two disk pair with the kernel and the absolute minimal tools to get started.
• MCC Interim Linux, which was made available to the public for download on the FTP server of University of Manchester in February, 1992;
• TAMU, created by individuals at Texas A&M University about the same time, and
• SLS (Softlanding Linux System).
• Yggdrasil Linux/GNU/X, created the first CD-ROM based Linux distribution.