Once an XFree86 server is running, X client applications can connect to it and create a GUI for the user. A range of GUIs are possible with Red Hat Linux, from the rudimentary Tab Window Manager to the highly developed, interactive GNOME desktop environment most Red Hat Linux users are familiar with.
To create the latter, more advanced GUI two main classes of X client applications must connect to the XFree86 server: a desktop environment and a window manager.
A desktop environment brings together assorted X clients which, when used together, create a common graphical user environment and development platform.
Desktop environments have advanced features which allow X clients and other running processes to communicate with one another and allow all applications written to work in that environment to perform advanced tasks, such as drag and drop operations.
Red Hat Linux provides two desktop environments:
GNOME — The default desktop environment for Red Hat Linux based on the GTK+ 2 graphical toolkit.
KDE — An alternative desktop environment based on the Qt 3 graphical toolkit.
Both GNOME and KDE have advanced productivity applications, such as word processors, spreadsheets, and Web browsers as well as provide tools to customize the look and feel of the GUI. Additionally, if both the GTK+ 2 and the Qt libraries are present, KDE applications can run in GNOME and visa versa.
For information on the customization of the GNOME and KDE desktop environments, refer to the Red Hat Linux Getting Started Guide.
Window managers are X client programs which are either part of a desktop environment or, in some cases, standalone. Their primary purpose is to control the way graphical windows are positioned, resized, or moved. Window managers also control title bars, window focus behavior, and user-specified key and mouse button bindings.
Five window managers are included with Red Hat Linux:
kwin — The KWin window manager is the default window manager for the KDE desktop environment. It is an efficient window manager which supports custom themes.
metacity — The Metacity window manager is the default window manager for the GNOME desktop environment. It is a simple and efficient window manager which supports custom themes.
mwm — The Motif window manager, is a basic, standalone window manager. Since it is designed to be a standalone window manager, it should not be used in conjunction with the GNOME or KDE desktop environments.
sawfish — The Sawfish window manager is a full featured window manager which was the default for the GNOME desktop environment until the release of Red Hat Linux 8.0. It can be used either standalone or with a desktop environment.
twm — The minimalist Tab Window Manager, which provides the most basic tool set of any of the window managers and can be used either standalone or with a desktop environment. It is installed as part of XFree86.
These window managers can be run without desktop environments to gain a better sense of their differences. To do this, type the xinit -e <path-to-window-manager> command, where <path-to-window-manager> is the location of the window manager binary file. The binary file can be found by typing which <window-manager-name>.