Unix for Advanced Users - X and Simple X Configuration

16. X and Simple X Configuration

16.2 Is it a Client or is it a Server?

No one really knows why (perhaps the X11 project started before the prevalence of what we now call the client-server environment?) but X uses a client-server paradigm which is diametrically opposite to what one would expect. Since this may be a bit confusing, we will elaborate.

In modern client-server world, a client is usually a small program which runs on your desktop. It connects over the network to a remote server (which is a program running on a more substantial box somewhere) and sends commands which the server understands. These commands make the server do something and return results back to the client.

The X server, on the other hand, runs on your desktop. An X client may be running locally (such as an xterm running from your hard disk) or running on a remote machine. If it is running on a remote machine and displaying on your desktop, the remote machine is connected using the X protocol to the X server running on your desktop. The X server understands the X requests coming from the remote machine to display the remote xterm.

Read the previous two paragraphs repeatedly until this issue is completely clear in your mind.

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