In Mac OS X, how do I run the X Window System?

Because Mac OS X is based on Unix, providing the X Window System (X11) for it has been a high priority for many developers, including Apple. All of the X11 implementations currently available include special window managers that let you use X11 applications alongside Aqua. Since the release of Apple's X11 for Mac OS X, however, most of the projects below have lost momentum, though the code for each is still available for download:

X11 implementations

Apple's X11

Apple has released its own version, which is far easier to install, and is included as an optional install on the installation disc (OS X 10.3 and later). Download Apple's X11 implementation from the Apple web site.

As noted in the above document, if you are using Tiger, you should use the X11 installer package on the Tiger disc.

For information about running X11 in Mac OS 10.4, see Running X Window System applications at the Apple knowledge base.

OroborOSX

OroborOSX has been released under the GPL.

XTools

Tenon Intersystems has released its own implementation called Xtools, which costs $200 but includes technical support. For information about Xtools, see Tenon's XTools web site.

X Window servers

X.org and XFree86 are the two most common X Window servers. They provide the back-end on which X11 applications run.

X.org

Most Unix window managers are migrating their code base to work with X.org, which is a fork off of the XFree86 project. You can download the source code from the X.org web site.

XFree86

XFree86 is the X server commonly used in GNU/Linux. Although the project has largely been abandoned in favor of X.org, XFree86 is still available as source code, which you may compile on your own, from the XFree86 home page.