Chapter 7. The X Window System and VNC

Although the X in “Mac OS X” is not the same X as in “the X Window System,” you can get them to play nicely together.

Most Unix systems use the X Window System as their default GUI. (We’ll refer to the X Window System as X11 instead of X, to avoid confusion with Mac OS X.) X11 includes development tools and libraries for creating graphical applications for Unix-based systems. Mac OS X does not use X11 as its GUI; it relies instead on the Quartz Compositor, which manages all onscreen activity, including the windowing environment. However, Apple’s own implementation of X11 for Mac OS X, based on the X.Org Foundation’s open source X11 (, is bundled with Mac OS X. (In Mac OS X 10.4 Tiger, X11 was not installed by default, although it was available as an optional installation on the Mac OS X install media.) Apple also provides an X11 software development kit (the X11 SDK) that is installed along with the Xcode tools (it is a component of the Unix Development Support package, which is selected by default during the Xcode installation).

This chapter highlights some of the key features of Apple’s X11 distribution and explains how to use X11 in both the rootless and full-screen modes. You’ll also learn how to connect to other X Window systems using Virtual Network Computing (VNC), as well as how to remotely control the Mac OS X desktop from remote X11 systems.

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