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In 1993, several major software and hardware vendors joined together in an effort to eliminate many of the arbitrary and confusing discrepancies among the various versions of UNIX. These ranged from the monumental, such as key programming interfaces that made it difficult for software developers to support several UNIX versions, to the less complicated but no less bothersome or expensive issues, such as unnecessary variations in file locations, formats, and naming conventions. Regardless of how "big" these differences were, the vendors recognized that some standardization would have to take place if UNIX were to continue to withstand the tough competition provided by Microsoft's Windows NT, which was finally becoming a serious competitor to UNIX in the server arena.
As a solution to the problem of inconsistent user interfaces, the Common Desktop
Environment (CDE) was presented in 1995 by Hewlett-Packard, Novell, IBM, and SunSoft (the
software division of Sun Microsystems). The CDE addresses not only the problem of
inconsistencies among versions of UNIX and among OEM versions of X Window, but also
greatly increases the accessibility of UNIX to nontechnical users accustomed to environments such
as Windows and Macintosh. The CDE not only presents the same "look and feel" on all
supported platforms, but it also provides base applications—such as a networked
workgroup calendar, a printer manager, context-sensitive help, and file and application
managers—that enable a user to completely avoid the often intimidating shell prompt and occasionally
confusing man pages. However, a power user can choose to turn off some of these features and
interface directly with the shell and command-line tools while still enjoying a consistent
interface if he or she has to use more than one UNIX variant. The CDE is so consistent in
UNIX versions that many vendors even distribute much of the same documentation!
In this chapter, I will introduce the CDE implementation distributed by Red Hat Software and developed by TriTeal. This version is fully compliant with the standard developed by the major vendors and is delivered in Red Hat RPM format. Thus, any Red Hat user can easily install it and enjoy the benefits of an easy-to-use GUI interface that is virtually identical to that offered by commercial versions of UNIX, such as IBM's AIX, Hewlett-Packard's HP/UX, and Sun's Solaris, among others.
The Red Hat Package Manager (RPM) makes it easy to install any application delivered in the proper format. However, the TriTeal CDE is even simpler than most because the installation media supplied by Red Hat Software comes with a shell script that installs the packages for you. It is located in the top-level directory on the CDE CD-ROM and is named install-cde.
One reason for the shell script is that the CDE requires several other packages in order to operate properly. Another reason is to enable the user to easily alter the base installation directory. The RPM is fully capable of addressing both these issues, but because a significant part of the CDE's target market is the beginner or nontechnical user, the shell script is provided so
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that it can quietly handle the dependencies and interactively prompt the user for installation options. A script with the same name and interface is also supplied with other versions of the CDE, so its inclusion further provides consistency with other platforms and vendors.
The packages required by the CDE are typical of standard Red Hat installations. The required set includes the following:
All these packages are included on the CDE media, so these dependencies are not an issue. The default root directory for the CDE software is /usr/dt, so it is important that the workstation have the required disk space, about 40MB, available in the appropriate partition. However, because the shell script asks the user if another directory should be used, it shouldn't be a problem if the required free space is only available in another partition.
| CAUTION |
The CDE packages configure the system to automatically start the CDE login manager after a system reboot. Because the login manager runs under X Window, it is important that X Window be configured correctly before the CDE is installed. |
After the installation script is run, the system should be rebooted. The CDE login manager starts in the last part of the initialization process. If you are watching the system as it initializes, you will see the normal console prompt, but don't bother trying to log in. The login manager will appear shortly, depending on how long it takes X Window to initialize on your system.
The login manager (dtlogin) screen is based on an older X Window application called xdm. With it, users are logged directly in to X Window, not only without having to run a shell script such as startx, but also with a default environment that can be configured in advance by the system administrator to suit the local environment. Much of this configurability is derived from xdm, but like much of the CDE, dtlogin adds a lot of new features. From the user's perspective, the login process is simple: Type in the username and press Enter. Then enter the password and press Enter again. dtlogin also enables a user to select the type of session he or she wants to start. These sessions can be specified by the administrator, but the default setup will probably suit most users' needs: