X servers

the X.Org Foundation's display server for the X Window System

XFree86 is an implementation of the X Window System. It was originally written for Unix-like operating systems on IBM PC compatibles and was available for many other operating systems and platforms. It is free and open source software under the XFree86 License version 1.1. It was developed by the XFree86 Project, Inc. The lead developer was David Dawes. The last released version was 4.8.0, released December 2008. The last XFree86 CVS commit was made on May 18, 2009; the project was confirmed dormant in December 2011.

Xgl is an obsolete display server implementation supporting the X Window System protocol designed to take advantage of modern graphics cards via their OpenGL drivers, layered on top of OpenGL. It supports hardware acceleration of all X, OpenGL and XVideo applications and graphical effects by a compositing window manager such as Compiz or Beryl. The project was started by David Reveman of Novell and first released on January 2, 2006. It was removed from the X.org server in favor of AIGLX on June 12, 2008.

Xming is an X11 display server for Microsoft Windows operating systems, including Windows XP and later.

XQuartz is an open-source version of the X.Org X server, a display server for the X Window System (sometimes shortened to X11 or X) that runs on macOS. In 2012, it formally replaced Apple's internal X11 app for OS X Mountain Lion (version 10.8). The name "XQuartz" derives from Quartz, part of the macOS Core Graphics framework, to which XQuartz connects these applications. XQuartz allows cross-platform applications using X11 for the GUI to run on macOS, many of which are not specifically designed for macOS. This includes numerous scientific and academic software projects.

Cygwin/X is an implementation of the X Window System that runs under Microsoft Windows. It is part of the Cygwin project, and is installed using Cygwin's standard setup system. Cygwin/X is free software, licensed under the X11 License.

Xsun is an X Window System (X11) display server implementation included with Solaris, developed by Sun Microsystems. It replaced the older Xnews server, which supported the display of not only X11 applications, but also NeWS and SunView programs. Xsun discontinued support for these legacy environments, and added support for Display PostScript.