Introduction to the X Window System

Chapter 17. Using X Window System Applications

IN THIS CHAPTER

• Introduction to the X Window System

• Installing the X Window System

• Using X

In this chapter, we introduce the X Window System, Unix's favored graphical user interface (GUI). If we haven't convinced you that this Unix stuff is too confusing (and we hope we haven't!), you shouldn't be bothered by the fact that the X Window System is rather different from both the Mac OS GUI and the Mac OS X Aqua GUI, and that frequently it exists best as a completely separate graphical interface.

NOTE

We have a few too many Xs to go around. The X Window System, though, has had its X for two decades longer than Mac OS X, so we have to get used to the nomenclature. The X Window System is usually referred to as X#, where # is the major revision number. Alternatively, you might see X#Rn, where # is the major revision, and n is the minor revision. As of this writing, X11R6 is the current version, but it is generally referred to as X11, or more simply, just X. X for the X Window System is pronounced as the letter X, not the number 10, as Mac OS X is supposed to be said.

Both a bit of a boon and a bane to the new Mac OS X user, the X Window System will be an important, if somewhat confusing, feature of Mac OS X for some time to come. As the de facto standard for Unix GUI applications, you'll find that a considerable amount of software has been written to use the X Window System. Much of this software will probably be slow in being ported to the Aqua GUI interface, and some might not be ported at all. Because of this, if you want to make the most use of the available Unix software, it's necessary for you to install the software to enable you to use the X Window System and get to know a little about the way that the interface works.

In earlier versions of Mac OS X, if you wanted to use X11, you needed to invest a bit of effort in installing it, or purchase a commercial product that installed it and integrated it with Aqua. With Mac OS X 10.3, Apple has started providing its own version of X11. Actually, it's a modified version of an open source X11 product. As an actively developed open source application, Apple's X11 version can be installed as a custom installation option, and either it or some other version of X11 for Mac OS X, is necessary to use applications written for X11. The new Apple installer, potentially combined using Fink or DarwinPorts to install applications, makes installation and use of X11 software a completely painless experience.

This chapter provides a basic introduction to X11, an explanation of how the X Window System interacts with the Mac OS X Aqua interface, and a brief discussion of some interesting X applications.