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Common Desktop Environment

Recent upgrades of ECN Sun Solaris systems to version 2.5 and the HP-UX systems to version 10.20, has introduced a new user interface. The Common Desktop Environment (CDE) is the result of the combined effort of Sun, HP and IBM to create a UNIX graphical interface which will have the same 'look and feel' across their UNIX systems. It is also designed to make UNIX easier to use. This interface appears on the AIX (4.1 and later) operating system.

CDE was designed to use previously developed Graphical User Interface (GUI) tools which allow current applications to more easily coexist with the interface. The X Window system (X) and Motif toolkit were chosen to support CDE due to their widespread availability and acceptance.

Today, most ECN UNIX systems run CDE by default. It is recognized by the login screen which displays a dialog box instead of a login prompt. To start a CDE session, a UNIX login ID is entered in the input area and then the ENTER key is pressed or the OK button is clicked. The dialog box then changes to prompt for a password which is entered in the same manner. If an error is made during the login process, the Start Over button may be clicked to clear all entered information. Clicking anywhere on the background screen causes the login screen to be refreshed.

The login screen allows a choice of interfaces via the Options button. Most machines will allow a command line or non-graphic login as well as a failsafe session which uses a limited window manager. The default interface is the last used, with the exception of command line or failsafe.

The system creates a file named .dtprofile in your home directory. The file may be modified to control your environment. At the end of the file, the line "DTSOURCEPROFILE=true" may be uncommented to include your .login file in the startup process. Using the "failsafe" login session may be helpful if your .login file does not successfully run under CDE.

After logging in, a CDE window manager session sets up an environment which may be customized to fit individual needs and preferences. The front panel, which is the main interface tool, will appear at the bottom of the screen and will always be displayed in all workspaces. The initial session will launch a Help window with an introduction to CDE and a File Manager window.

The front panel is a special desktop window which contains controls to launch often used applications. It consists of a main panel and subpanels. The main panel, which is always visible when the front panel is not minimized, contains controls for launching applications, displaying system information, selecting workspaces and opening subpanels. Subpanels are indicated by an arrow above a main panel control and display a pop-up list of applications usually related to that control. Clicking on the subpanel arrow toggles its display.

The default controls display system information including the current time, date, mail status and busy status for the host. The calendar, file manager, text editor, mail reader, printer control, style manager, application manager, help system and trash can applications may all be launched from front panel controls. The printer and trash can controls may also be used in a drag and drop fashion to print and delete files.

The ability to use multiple workspaces is one of the most useful features of the CDE. The center section of the front panel contains controls for working with workspaces. Workspaces simulate multiple display screens. By default, four workspaces are defined, but more may be added if needed. Each workspace is a virtual screen with its own background and set of displayed applications. Application windows may be moved or shared between displays allowing a large number of applications to be active while avoiding too much clutter on the screen. The current workspace is indicated by the shading of the workspace buttons, with its workspace's button appearing depressed. Changing workspaces is performed by clicking on one of the workspace buttons. The buttons may be labeled to reflect the workspace use.

A popular feature of CDE is its ability to reconstruct the same environment during each login independent of the machine last used. Applications running at the time of logout can be restarted and displayed in the same workspace area in which they were last running. This is done by saving the information needed to restart applications running during the logout process. A home session may also be saved which will restore the same environment no matter what applications may have been running at the time of the last logout. The choice of behavior is set using the desktop style manager. Separate environments may also be created for specific hosts or displays. In this case, the changes in one environment will have no effect on any other environment. This feature is handy for automatically launched applications which should not be launched from multiple hosts, for example, an application which creates lock files or is not available on all platforms supporting CDE.

Automatic startup is limited to CDE actions. Programs which are started otherwise, such as from within a terminal window, do not save information in the CDE environment. In the case of an application started from a terminal window, the terminal window application will be started, but will only contain a shell session. Also, applications in the ECN environment started indirectly by scripts may not be displayed in the workspace where they last appeared. These may be launched if desktop actions are defined for them, but the display will appear in the current workspace rather than its original one.

The EXIT control closes the CDE session. A dialog box confirms the logout request and warns that data may be lost if applications have not been shut down correctly. It also notes that some applications (ones not launched as CDE actions) may need to be restarted upon login. Clicking Continue\ Logout causes all current applications to exit, the session environment to be saved, and the login screen to be displayed. Clicking Cancel Logout will clear the dialog box and return to the current session with no further action. The session may also be ended by clicking the right mouse button anywhere on the CDE background and choosing Logout from the menu displayed.

Information on setting up multiple environments, customizing the session environment, managing sessions, using the built in CDE applications, and creating CDE actions can be found in the CDE User's Guide available in the ECN library.

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