linux graphical user interface
linux provides two basic types of interface for you to use when working with your computer: gui (graphical user interface) and cli (command-line interface). in addition, two methods to deal with graphical user interface are described here, which are window manager and desktop manager.
1- window manager
• the underlying engine of x11 is the x protocol, which provides a system of managing displays on local and remote desktops. the protocol uses a client/server model that allows an abstraction of the drawing of client windows and other decorations locally and over a network. an x server draws client windows, dialog boxes, and buttons that are specific to the local hardware and in response to client requests. the client, however, does not have to be specific to the local hardware. this means that system administrators can set up a network with a large server and clients and enable users to view and use those clients on workstations with totally different cpus and graphics displays.
• because x offers users a form of distributed processing, this means that fedora can be used as a very cheap desktop platform for clients that connect to a powerful x server. the more powerful the x server, the larger the number of x-based clients that can be accommodated. this functionality can breathe new life into older hardware, pushing most of the graphical processing on to the server. a fast network is a must if you intend to run many x clients because x can become bandwidth-hungry.
• x is hugely popular in the unix and linux world for a variety of reasons. the fact that it supports nearly every hardware graphics system is a strong point, as well as strong multi-platform programming standards give it a solid foundation of developers committed to x. another key benefit of x is its networking capability, which plays a central point in administration of many desktops and can also assist in the deployment of a thin-client computing environment. being able to launch applications on remote desktops and also standardize installations serve to highlight the versatility of this powerful application.
• popular window managers include after step, black box, fluxbox, fvwm, icewm, kwm, metacity, twm, vtwm, and window maker.
2- desktop manager
2-1 what is a desktop
the desktop represents the workspace of the graphical user-interface. it is based on the so called desktop-metaphor. the overall concept is to sympathise real-life objects (appearance and handling) to the elements on the display. this also concerns symbols, programs, system elements, files and storage media. furthermore a trash container belongs to this concept. the technical implementation of the desktop-metaphor is done by the desktop-environment. in the following we will describe two of the most important and wide-spread unix/linux desktops. of course there are a lot more than these.
different distributions provide different desktops, but most provide kde (k desktop environment) and/or gnome (gnu network object model environment) the big two of linux desktops. the default desktop differs by distribution. for instance, fedora defaults to gnome, and mandrake/suse defaults to kde.
2-1-1 gnome – the gnu network object model environment
the gnome project was initiated 1997 by miguel de icaza. at this time, only proprietary desktops like cde existed and the kool desktop environment (today kde) was based on the qt-toolkit which was felt “unfree” by some developers. as trolltech (developer of qt) did not respond to any request to change the license, it was decided to build gnome upon the gimp toolkit gtk+. furthermore it was decided to use c instead of c++ (kde). developers promised an easier and higher portability and an improved link to other programming languages. as for now there exist language-interfaces i.e. for c++, c#, java, python, perl and guile.
url: http://www.gnome.org/
licence: gpl and lgpl ships with i.e.: redhat, fedora core, debian, ubuntu, foresight linux
2-1-2 kde – the k desktop environment
kde is an adequate, consistent and easy to use desktop for unix-like systems and was founded in 1996 by matthias ettrich. it is based on the qt toolkit which became gpl in the year 2000. kde, like gnome, is a free desktop environment. kde is primarily a volunteer effort, although various companies, such as novell, trolltech and mandriva employ developers to work on the project. 3 kde is known as a flexible user interface. configuration possibilities range from optical settings to changes of the kde behaviour. in addition kde is available in over 50 languages.
url: http://www.kde.org/
licence: gpl and lgpl ships with i.e.: suse, mandriva, slackware, kubuntu, knoppix
2-1-3 other desktops there exist a lot of other interesting free desktop environments for linux. the list below shows some of them:
however they will not be described further here because of their low acceptance and most of them are gone out of date. in this example we stick to the already established ones and will give some guidance to choose your own from these. of course it is possible to include more desktops in an own evaluation.
2-2 which is right for me?
main criteria for the selection:
• stability
• efficiency
• usability (ease of use, customization, ...)
• applications
• office suite
• technology
users will have the last word. in addition,
a statistics shows that:
• gnome is used about 65% of gnu/linux desktop.
• kde is about 26% utilized.
2-3 exploring gnome desktop
1. top panel: a panel is a special portion of your desktop, controlled by the gnome-panel application, which provides access to various ways of interacting with the desktop and launching different types of applications. gnome can display panels along any edge of the screen, but the default gnome configuration displays panels at the top and bottom of the screen. by default, the top panel contains the following items:
2. applications, places, and system menus: a menu consists of a list of shortcuts to specific commands, tasks, or applications. these three menus provide easy, graphical access to applications, portions of your computer system or network locations, and system-related tasks, respectively. each of these menus is described in more detail in the next section, “menus in gnome.” to display any of these panel menus, you simply left-click on the name of the menu, and the associated menu dropings down and displays on your screen. to close the menu, simply left-click elsewhere on the screen.
3. application launchers: these icons start specific applications for you when you left-click on them.
4. applets: these icons launch lightweight applications that run in the context of a panel and provide various capabilities.
5. log out button: this button quickly terminates your current login session and re-displays the gnome login manager.
6. workspace: this is the portion of the screen in which applications execute and display associated windows and dialogs.
7. bottom panel: this panel is displayed at the bottom of the screen and contains the following items by default:
8. show desktop button: this button minimizes all windows and dialogs that are currently displayed on the screen, revealing the current desktop.
9. application controls: each application that is active on your current workspace displays an associated control region in this portion of the bottom panel. right-clicking on this control minimizes and maximizes the application, while left-clicking on this control displays a context-sensitive menu for moving and controlling that application’s window(s).
10. workspace switcher: this is a special applet that enables you to manage multiple workspaces and provides a miniature display of each active workspace. workspaces are essentially separate virtual screens that are provided by the gnome desktop. you can run applications on different workspaces, move applications between workspaces, and so on. multiple workspaces provide a convenient way of running different types of applications on different virtual screens without them being visible until you actually switch to the workspace where they are displayed. a common example of when this is useful is when you’re at work and want to play a game — you can start the game on a different workspace from the one where you’re actually working, and switch to it whenever no one is looking over your shoulder.
11. trash applet: this is a special applet that provides access to the trash can, which is a special portion of the gnome desktop to which you can drag files to subsequently deleting them.