Window Managers An Introduction to the X Window System

Nevertheless, to come out with the issue of a philosophy of X administration, it would be that X is made to fit the needs of its users. The administrator has the responsibility to determine the users need and configure X accordingly. X is installed in all sorts of environments, from academia, via industry, to home offices with a single standalone machine. For that reason, almost everything in X is configurable at multiple levels. The X Display Manager can be configured in several different places, to meet practically any need. Even the source code to X is available for those who want to create their own workarounds. The fundamental idea is that if you do not like the way something is working, change it. We will continue our discussion about X having in mind the standard X distribution, especially its CDE release. However, to copy with the CDE, an appropriate knowledge of older X releases is required. Finally, through a number of examples we will also touch some vendor−specific flavors mostly HP VUE. The full understanding of the standard X distribution is a giant step in maintaining other vendor−specific X flavors.

22.1.3 Window Managers

From the previous discussion it is obvious that window managers play a special role among all X programs. A few relatively simple tasks in managing a window — open, move, resize, close, pop−up, and pop−down menus — create a formidable working space that fundamentally changed the man−machine interface. Today, the window environment not necessarily X windows is a common working environment for almost every user. The original MIT window manager was the twm — Tab Window Manager. It was the only window manager provided in the MIT X distribution. There are also many other window managers distributed by vendors. One of the most popular window managers is mwm, the Motif Window Manager which implements the OSFMotif look and feel OSF stands for open system foundation; OSFMotif also includes a complete graphic user interface. Another popular window manager was olwm, a window manager for OPEN LOOK. Other window managers were: swm − the Solbourne Window Manager — which can simulate both olwm and mwm in separate modes; gwm, a public domain window manager that can simulate mwm; and tvwm and olvwm, which present versions of twm and olwm respectively, but they support a virtual root window. A root window is larger than the portion visible on the display, and it can be scrolled around to bring different sections into view. Today, the CDE Desktop Window Manager dtwm is probably the most attractive; it was based on the OSFMotif mwm, version 1.2.4. Although, the administration is more or less similar for different window managers, some discrepancies are possible. Consulting the corresponding vendors documentation is always recommended. We will discuss this issue regarding the mwm, dtwm, and occasionally, twm. Most of the examples are mwmdtwm related. A window manager is normally invoked through the users startup script when an X session is started. However, the window manager could be also started from the command line, as any other UNIX program. For example: dtwm will invoke CDE DT Window Manager in the background 518 Figure 22.2: The CDE terminal emulator dtterm supported by dtwm. By moving the cursor pointer into the windows titlebar, and holding down the left mouse button, the window could be moved. By pressing small icons at the upper right corner of the titlebar, the window could be resized or iconified. Pop−down menus are also available to handle window, select options, and others. Different X flavors do have different X−based terminal emulators; they are functionally similar, but the contiguous esthetic, and sometimes functional, improvements are evident. An older version of the X−based terminal, xterm, launched on SunOS 4.1.3 platform is presented in the Figure 22.3. 519 Figure 22.3: The X terminal emulator xterm supported by twm. The behavior of a window manager could be configured by editing its configuration files in several ways; one of the ways is to manage the configuration file in an individual users directory for mwm the local configuration file is .mwmrc; correspondingly, for tdwm is the .dtwmrc file, for twm the .twmrc, etc. The default behavior of the window manager at the system level could be configured via the system.mwmrc file for mwm, and correspondingly: system.dtwmrc, or system.twmrc. We will discuss in more detail the window manager s configuration administration later in the text.

22.2 The X Display Managers