is Apple Computer
's implementation of the X Window System
for Mac OS X
. Apple's implementation of X11 is based on the X.Org Server
and adds support for hardware-accelerated 2D graphics
, hardware OpenGL
acceleration and integration with Aqua
, the Mac OS X graphical user interface
(GUI). X11.app was initially available as a downloadable public beta
for Mac OS X v10.2
and later included as a standard package in Mac OS X v10.3
, which can be downloaded from Apple's website. In Mac OS X v10.4
, X11.app was an optional install included on the install DVD. Since Mac OS X v10.5
, X11 is installed by default. There is no official way to install X11.app on 10.4 or 10.5 without the install DVD.
In 10.4, Apple's X11.app implemented X11 protocol release 6.6 (X11R6.6). This implementation includes an XFree86 4.4 based X11 window server, Quartz rootless window manager, libraries, and basic utilities such as xterm. "Rootless" means that X window applications show up on the Quartz desktop, appearing like any other windowed Quartz application (i.e. not in a virtual desktop contained within another window). In Mac OS X v10.5, X11.app was rewritten to use the more popular X.Org Server (X11R7.2) rather than XFree86.
The source code for X11.app is available from Apple under the Apple Public Source License.