As we have seen, an X-Window implimentation operates as a client/server model. Thus, it is not uncommon for graphical applications under UNIX to be called "X Clients".
This simply means that whatever X application you run on your local machine, will also be able to be ran remotely from another machine.
The implications of this are really quite amazing. For example, instead of having to install an application on every machine in your lab, you could just install it on one "server" machine and utilize it remotely on the rest.
This is, in fact, a large portion of Sun Microsystem's main business. They often market and sell servers with smaller, less expensive client machines that only run their applications from the server.
There are even devices known as "X Terminals" which are stripped machines only running X Client software. These machines can be used to run X applications from an X server somewhere in very inexpensive ways. Here is a link with some (slightly older) X Terminals for $30 each: http://www.computersurplusoutlet.com/viewproduct.asp?PID=NET-HDSVS
As another example, you can run graphical utilities and tools from remote machines performing administrative tasks without having to be physically located at the remote machine.
Window Managers and Desktop Environments
The X Window system really only supplies the basics of a windowing system. There is no (or little) support for widgets, decorations, window management, and various interface schemes. Instead, additional applications must be built upon the X Window system that provide the actual user-interface items.
These applications traditionally fall under two different concepts: Window Managers and Desktop Environments.
Window Managers are typically lighter user-interface environments with sometimes reduced functionality. Desktop Environments, on the other hand, are usually large and featureful user-interface environments supplying such items as desktop icons and links, backgrounds and screensavers, unified widget sets, scripting, theming, and more. Desktop Environments usually include a Window Manager associated with them as well suites of applications.
A Desktop Environment is typically larger and more demanding on system resources than a Window Manager. Sometimes, if memory or hard drive space is lacking, it is recommended to use a Window Manager over a full Desktop Environment.
While there are many environments that are definately a "Desktop Environment" or a "Window Manager", there are many others that have traits and qualities of both. Thus, in many cases, the classifications become blurred.
Multiple Desktops
One of the keenest features you will find in most UNIX Window Managers and Desktop Environments is the ability to use Multiple Desktops. Using multiple desktops you can organize your applications by desktops, conserving on precious screen real estate.
Many people new to Linux do not immediately see the benefits of having multple desktops. However, as they use it more and more, many people find it indespensible. Thus, many people exposed to it find they cannot live without it on Windows systems. If you become one of these poor souls, then Win32 apps such as JSPager (http://hem.fyristorg.com/jspage/) are for you.
