When you login to a workstation, usually you just have a shell
running. (On DECstations and Vaxstations, X is run for you. On X
Terminals, a display manager program on some client machine will run
some kind of login session on the terminal (which is running the
display server - one performance hit for an X terminal is that the
window manager may be running in the client machine, so events may
have to make an extra round trip time if the window manager is
interested in them).
Otherwise, to run X-Windows, you have to set up quite a lot of parameters, but
it is worth the effort, as your productivity goes up pretty fast after
that.
You need to initialize X in some way - this means you need to start
a display server for your display.
You then need at least one application - e.g. an xterm running a
shell.
The process model of X is roughly as shown in figure #fnxproc#1664>
#figure1665#
Figure: Process Model of X