Department of Physics and Astronomy - Computer Facilities

Brief Introduction to CDE

Most major Unix vendors now provide the CDE as standard. Consequently, most users of the X Window system will now be exposed to the CDE. Indeed, continuing trends in the development of Motif and CDE will probably lead to a convergence of these technologies in the near future. This section highlights the key features of the CDE from a Users perspective.

Upon login, the user is presented with the CDE Desktop. The desktop includes a toolbar at the bottom, multiple virtual workspaces (accessed from panels labeled One through Four on the toolbar), and window management menus. First time user will encounter empty workspaces. Literaly everything can be customized. One should start with Style Manager (see picture below for its location on the toolbar). Startup option in it can set the default appearance of the CDE desktop on future log-ins (major choice is between launching some standard set, one have saved as default or launching exact copy of the end of the last session).

The toolbar contains a set of icons and menus that appear at the bottom of the screen, by default. The front panel contains the most regularly used applications and tools for managing the workspace. Users can drag-and-drop application icons from the file manager or application manager to the popups for addition of the application(s) to the associated menu. The user can also manipulate the default actions and icons for the popups. The front panel can be locked so that users can't change it. A user can configure several virtual workspaces -- each with different backgrounds and colors if desired. Each workspace can have any number of applications running in it. An application can be set to appear in one, more than one, or all workspaces - simultaneously. Most toolbar options are also available from the menu which appears when one right-clicks on the empty portion of the screen.

CDE includes a standard file manager. Users can directly manipulate icons associated with UNIX files, drag-and-drop them, and launch associated applications by double-clicking them.

Desktop toolbar tools include the following (please familiarize yourself with all menu options for best results):

Mail Tool
Used to compose, view, and manage electronic mail through a GUI. Allows the inclusion of attachments and communications with other applications through the messaging system. This is true in general, however for the time beeing Mail Tool on our CDE is intentionally disabled for security purposes. We encourage people to use other mail programs, such as Pine and Netscape.
Calendar Manager
Used to manage, schedule, and view appointments, create calendars, and interact with the Mail Tool.
Editor
A text editor with common functionality including data transfer with other applications via the clipboard, drag and drop, and primary and quick transfer. It is simple editing tool that we advise to be used for a smaller and simpler tasks. Use of Emacs or Xemacs as most versatile editing tools available is encouraged. You can launch them using emacs & or xemacs & commands from the terminal window.
Terminal Emulator
An xterm terminal emulator.
Calculator
A standard calculator with scientific, financial, and logical modes.
Print Manager
A graphical print job manager for the scheduling and management of print jobs on any available printer.
Help System
A context-sensitive graphical help system based on Standard Generalized Markup Language (SGML). It will be launched as default on your first session.
Style Manager
A graphical interface that allows a user to interactively set their preferences, such as colors, backdrops, and fonts, for a session.
Icon Editor
This application is a fairly full featured graphical icon (pixmap) editor.

All applications inside CDE run within windows contained within window frames. Brief summary of its features and controls follows:

Title Bar (located on the top of the window). It identifies the window by a text string. The string is usually the name of the application. However, an application's resource controls the label, ie. it can be manipulated.
Window Menu
Every window under the control of window manager has a window menu. The application has a certain amount of control over items that can be placed in the menu. The Motif Style Guide insists that certain commands are always available in this menu and that they can be accessed from either mouse or keyboard selection. The action from the keyboard usually involves pressing two keys at the same time: the "meta key" and another key. The default window menu items and mnemonics are listed below:

Minimize Button
another way to iconify a window.
Maximize Button
another way to make a window the size of the root window.

The window manager must also be able to manage multiple windows from multiple client applications. There are a few important issues that need to be resolved. When running several applications together, several windows may be displayed on the screen. As a result, the display may appear cluttered and hard to navigate. The window manager provides two mechanisms to help deal with such problems:

Active Window
Only one window can receive input at any time. If you are selecting a graphical object with a mouse, then it is relatively easy for the window manager to detect this and schedule appropriate actions related to the chosen object. It is not so easy when you enter data or make selections directly from the keyboard. To resolve this only one window at a time is allowed keyboard focus. This window is called the active window. The selection of the active window will depend on the system configuration which the user typically has control over. There are two common methods for selecting the active window:
Focus follows pointer
The active window is the window is the window underneath mouse pointer.
Click-to-type
The active window is selected, by clicking on an area of the window, and remains active until another window is selected no matter where the mouse points. This option is advantageous in avoiding frequent mistakes when many windows are open at the same time.
When a window is made active its appearance will change slightly:

The exact appearance of the above may vary from system to system and may be controlled by the user by setting environment settings in the window manager.

Window tiling
Windows may be stacked on top of each other. The window manager tries to maintain a three-dimensional look and feel. Apart from the fact that buttons, dialog boxes appear to be elevated from the screen, windows are shaded and framed in a three-dimensional fashion. The top window (or currently active window) will have slightly different appearance for instance.

Iconification
If a window is currently active and not required for input or displaying output then it may be iconified or minimised thus reducing the screen clutter. An icon is a small graphical symbol that represents the window (or application). It occupies a significantly less amount of screen area. Icons are usually arranged around the perimeter (typically bottom or left side) of the screen. The application will still be running and occupying computer memory. The window related to the icon may be reverted to by either double clicking on the icon, or selecting Restore or Maximise from the icon's window menu.

For more information about using X windows at Rutgers University please see RUCS maintained page on this subject.

Richard Vaughn
Last modified: Wed Mar 29 16:11:32 EDT 2006