For most of the 1990s and early 2000s, the project was the source of most innovation in X and was the de facto steward of X development. Until early 2004, it was almost universal on Linux and the BSDs.
In February 2004, with version 4.4.0, The XFree86 Project adopted a license change that the Free Software Foundation considered GPL incompatible. Most Linux distributions found the potential legal issues unacceptable and made plans to move to a fork from before the license change. At first there were multiple forks, but the X.Org fork soon became the dominant one. Most XFree86 developers who were already annoyed at other issues in the project also moved to X.Org.
The XFree86 server communicates with the host operating system's kernel to drive input and output devices, with the exception of graphics cards. These are generally managed directly by XFree86, so it includes its own drivers for all graphic cards a user might have. Some cards are supported by vendors themselves via binary-only drivers.
Because the server usually needs low level access to graphics hardware, on many configurations it needs to run as the superuser, or a user with UID 0. However, on some systems and configurations it is possible to run the server as a normal user.
It is also possible to use XFree86 in a framebuffer device, which in turn uses a kernel graphics card driver.
On a typical POSIX-system, the directory /etc/X11 includes the configuration files. The basic configuration file is /etc/X11/XF86Config (or XF86Config-4) that includes variables about the screen (monitor), keyboard and graphics card. The program xf86config is often used, although xf86cfg also comes with the XFree86 server and is certainly friendlier. Many Linux distributions used to include a configuration tool that was easier to use (such as Debian's debconf) or autodetected most (if not all) settings (Red Hat Linux and Fedora's Anaconda, SuSE's YaST and Mandrake Linux used to choose this path).
As Linux grew in popularity, XFree86 rose with it, as the main X project with drivers for PC video cards.
By the late 1990s, official X development was moribund Most technical advancement was happening in the XFree86 project. In 1999, XFree86 was sponsored onto X.Org (the official industry consortium) by various hardware companies interested in its use with Linux and its status as the most popular version of X.
By 2003, while Linux's popularity, and hence the installed base of X, surged, X.Org was all but inactive and active development was largely carried out by XFree86. However, there was considerable dissent within XFree86. It was perceived as far too cathedral-like in its development model: developers were unable to get CVS commit access and vendors had to maintain extensive patches In March, long-term contributor Keith Packard was ejected from the Core Team with considerable ill-feeling The Core Team claimed that Keith had been trying to fork the XFree86 project by working inside the project while trying to attract core developers to a new X Server project of his own making. Packard denied this had been his aim.
Versions of XFree86 up to and including some release candidates for 4.4.0 were under the MIT License, a permissive, non-copyleft free software license. XFree86 4.4 was released in February 2004 with a change to the license: the addition of a credit clause, similar to that in the original BSD license, but broader in scope. Many projects relying on XFree86 found the new license unacceptable, and the Free Software Foundation considered it incompatible with the GNU General Public License. The XFree86 Project contests this, maintaining that the license is compatible with the GPL.
Some projects made releases (notably OpenBSD 3.5 and 3.6, and Debian 3.1 "Sarge") based on XFree86 version 4.4 RC2, the last version under the old license. Most operating systems incorporating XFree86 (including later versions of OpenBSD and Debian) migrated to the X.Org Server.
The X.Org Server became the official reference implementation of X11. The first version, X11R6.7.0, was a fork from XFree86 version 4.4 RC2, with X11R6.6 changes merged in. Version X11R6.8 added many new extensions, drivers and fixes. It is not encumbered by the XFree86 license changes. It is hosted by and works closely with freedesktop.org.
|Version||Release date||Most important changes|
|X386 1.1||February 11, 1991||First version by Thomas Roell, based on X11R4.|
|X386 1.2||August 29, 1991||Included with X11R5.|
|X386 1.2e 0.0||May 7, 1992||First pre-XFree86 code by eventual team members.|
|XFree86 1.0m||September 2, 1992||First version named "XFree86".|
|XFree86 2.0||October 1993|
|XFree86 2.1||March 11, 1994|
|XFree86 2.1.1||May 4, 1994||Last version based on X11R5.|
|XFree86 3.0||August 26, 1994||Release for X11R6.|
|XFree86 3.1||September 29, 1994|
|XFree86 3.2||October 26, 1996|
|XFree86 3.3||30 May 1997||XFree86 Acceleration Architecture (XAA)|
|XFree86 3.3.1||8 August 1997|
|XFree86 3.3.2||24 May 1998|
|XFree86 3.3.3||30 December 1998|
|XFree86 18.104.22.168||30 December 1998|
|XFree86 3.3.4||21 June 1999|
|XFree86 3.3.5||17 August 1999|
|XFree86 3.3.6||December 31, 1999||Last 3.x version.|
|XFree86 4.0||March 8, 2000||Complete new architecture. X11R6.4 included.|
|XFree86 4.0.1||June 30, 2000||XRender|
|XFree86 4.0.2||December 18, 2000|
|XFree86 4.0.3||March 16, 2001|
|XFree86 4.1.0||June 2, 2001|
|XFree86 4.2.0||January 18, 2002|
|XFree86 4.2.1||September 3, 2002|
|XFree86 4.3.0||February 26, 2003|
|XFree86 4.4.0||February 29, 2004||First version under XFree86 License 1.1.|
|XFree86 4.5.0||March 16, 2005|
|XFree86 4.6.0||May 10, 2006|
|XFree86 4.7.0||August 12, 2007|