1.2. Running X - the Server and the Client

1.2. Running X - the Server and the Client
	1. The X Window System

To use X, you need to run two different programs. One is an X server, the program that is responsible for controlling the display of the machine on which you are working. The other is an X client, which is simply an application program that was compiled to work with X. The server must run on the machine at which you are seated - it's job is to actually draw things on your display and handle mouse and keyboard inputs. The client program, on the other hand, might run on that same machine, but might also be something running on a remote machine somewhere on the Internet, such as one of our Dept. Unix machines.

To run X, then you need to

Run an X server on your local PC.
Launch an X client application on the remote machine.

This assumes, of course, that you have X server software installed on your local PC (or are carrying a portable X server on a flash drive). You may also need software to launch the remote application. Sometimes this comes with the server software. If not, almost any ssh software will do. If you've been using PuTTY, for example, for your telnet client, you can use it for ssh as well.

The course Library page has tips on what X servers and ssh programs are recommended, particularly for Windows PCs, and how to get them (for free or at a student discount). The choices that I will discuss in this chapter are:

Xming: an open-source X server for Microsoft Windows
Cygwin/X: another open-source X server for Microsoft Windows (from which xming was derived)

StarNet XWin-32: A commercial package licensed by ODU for student use

"native" X servers: if you are seated at a Linux or an Apple OS/X machine, you probably already have an X server and may have been using it without realizing it.

NX: a compressed, optimized variant of X that works much better in high-latency conditions. NX clients (unlike the above programs which are servers, for NX you want a "client" program) are available for Windows, Mac, and Linux machines.

You may need to get familiar with a few different X servers. That's because you will want something you can run at home, but will have to accept whatever is installed if you go into a computer lab to work.^[23]

On the ODU campus, if you go into one of the CS Dept computer labs, you will find the PCs are equipped with both Xming and StarNet X-Win32. OCCS labs (the general University computing labs) have StarNet X-Win32.

^[23]Actually, you can put Xming and portable PuTTY on a flash drive and carry a single X server with you wherever you go.


1.1. X - an Overview		1.3. Launching an X Server