Interacting with a UNIX system:

  There are two main points of interaction that a user has with
  a UNIX workstation.  The first is through a terminal, where you
  interact with a UNIX "shell".  These shells allow the user to
  use a suite of standard tools (and to create their own) and has
  a text-based interface.

  The second point of interaction is through X Windows.  X Windows
  is the name for the system that provides a graphical interface
  where a user can interact with several windows (called X clients)
  that are all beautified and manageable through a window manager
  (also an X client).

  X clients can be started from menus provided by the window manager,
  and from a shell.  A typical client is "xterm" --- an application
  that creates a terminal (with a shell running) in a new window.

  The Window Manager:

    The window manager is the application that is responsible for
    putting titlebars around windows, allowing the user to relocate
    and resize X clients, and (oftentimes) allows the user to separate
    the running applications into "virtual desktops".  Many window
    managers also provide the ability to hide and unhide windows.

    Our default environment uses a window manager called icewm, but
    many others are available.  These include "ctwm", "twm", "wmaker",
    and "fvwm".

    Each of these applications has configuration files that allow a
    user to customize the appearance and behavior of the window manager.

  XDM:

    There are two ways of starting X windows: Xinit and XDM.  With
    xinit, a user typically logs on to a machine though a typical
    text-based dialogue, then runs the command "xinit" to start a
    windowing session.  We don't use this system in the UofC CS
    department.  XDM is the system that we favor.  Under XDM, a
    user logs in through a graphical login screen, and then a
    user-customizable set of X clients (including their window
    manager) are started.  This start-up action is controlled by
    the users .xsession file (located in their home directory).

  There are a suite of popular X window clients including netscape,
  the acrobat reader (the command is "acroread") and so on.