As we discuss in detail later, the X window manager is a program which runs under X and controls the format, features, organization, placement, and response of X's windows. While you can run X without a manager, it is much more convenient and faster to have it managed. There are a number of free window managers available over the network. They are free and each produces a characteristic feel and look. It is these window managers which tailor X and give it the capability of making your workstation appear like a PC. In addition to the window manager, there are desktop programs such as xdt which convert your screen into a symbolic desktop with icons representing various files and functions, similar to what you find on the Macs. These desktop interfaces are excellent guides for providing beginners a tour, but tend to get in the way for power users.