Desktop +Read Chapter 10Screen layoutcalled geometryit is a bitmap with certain size of pixelstypical size is 1920 x 1200addressing pixelsspecific position on screen, e.g., 500 x 200position relative to corner of screen1Desktop +Screen layoute.g., +50+50 is 50 pixels away from the upper left corner of the screen in both X and Y direction2X Window System securityWho can have access to your screen?X server running a system only allows X client on that system to talk to it.X server does not allow connections from other X clients unless you explicitly allow it.3X Window System securityUtility: xhost [+|-][hostname]The xhost command allows or denies access to the X server on a system. With no arguments, xhost prints its current settings and which hosts (if any) have access. By specifying only +, you can give access to all hosts, or by specifying only -, deny access to all hosts. When a hostname is specified after a + or -, access is granted or denied, respectively, to that host.4X Window System securityUtility: xhost [+|-][hostname]For example: $ xhost +bluenoteallows X clients running on system "bluenote" to write to the display on the system where the xhost utility was run. Later, when whatever you needed to run is finished, you can disallow access with the command:$ xhost -bluenote5X Window System securityUtility: xhost [+|-][hostname]You can allow any X client on the network to write to your display with the command:$ xhost +You can also take away access to all remote X clients with:$ xhost -Where does it make sense to do this?6Desktop EnvironmentAll programs that manage and render the desktop, e.g., the icons, windows etc.menus providing access to objects, tasks, or applicationsicons representing devices or other objects in the systemstatus bars or areas where real-time status data is displayeda cursor controlled by a mouse providing navigation among and interaction with desktop objects7Desktop EnvironmentMost common Linux desktops The Common Desktop Environment (CDE) was one of the first true DEs for UNIX systemCDE is based in large part on Hewlett-Packard's Visual User Environment (VUE) and Sun Microsystem's OpenWindows.8Desktop EnvironmentMost common Linux desktops The GNU Network Object Model Environment (GNOME) is the GNU Project's contribution to desktop environment. Like other GNU software, it is freely available, is included in most Linux distributions.9Desktop EnvironmentMost common Linux desktops The K Desktop Environment (KDE) has been developed by a loose group of programmers around the world. KDE is included in most Linux distributions10Window ManagersA window manager is a program (an X client) that communicates with the X server and with the keyboard and mouse on the system. It provides the interface for the user to give instructions to the X server about what to do with the windows.Window manager provides “look and feel” of desktop11Window ManagersFocusFocus is the term used to describe which window is currently selected or active.e.g. if you type on keyboard, the window with focus is where the data will be sent.Typically the window with focus has different border, e.g., highlighted, darker shade etc.12Window ManagersMany choices, e.g.,dtwm The Desktop Window Manager (dtwm) is part of the CDE, and is similar to vuewm, discussed below, but supports a virtual desktop.fvwmfvwm is popular in the Linux community because of its free availability and because it is very customizable. fvwm is included in some Linux distributions. 13Window ManagersMany choices, e.g.,gnome-wmThe GNOME Window Manager (gnome-wm) is the window manager used with the GNU Network Object Model Environment (GNOME). 14Window ManagersMany choices, e.g.,icewmThe ICE Window Manager (icewm) is another grass-roots, popular window manager. It is small, fast, and easily customizable to resemble Windows so that PC users can feel comfortable using a Linux system. icewm is included in some Linux distributions. 15Window ManagersMany choices, e.g.,kwmThe K Window Manager (kwm) is used with the K Desktop Environment (KDE). While not required, it is recommended over other window managers for use with KDE because of its tight integration with KDE functionality. kwm is included in just about all Linux distributions.16Window ManagersMany choices, e.g.,mwmThe Motif Window Manager (mwm) is one of the first major window managers.olwmSun Microsystems' OpenLook Window Manager (olwm) and OpenLook Virtual Window Manager (olvwm) run on Sun systems and can be used with CDE.17Window ManagersMany choices, e.g.,twmTom's Window Manager (twm) and Tom's Virtual twm (tvtwm) were written by Tom LaStrange to correct some of the things he didn't like about mwm. tvm is included in many Linux distributions. tvm is also sometimes called the Tab Window Manager.18Window ManagersMany choices, e.g.,vuewmThe VUE Window Manager (vuewm) is from Hewlett-Packard and runs under HP's Visual User Environment (VUE) desktop.19Client ApplicationsMany choices, e.g.,Utility: xclock [-digital]The xclock command provides a simple clock on your desktop. The default is an analog clock. If the -digital argument is specified, a digital clock is displayed instead.Utility: xtermThe xterm command starts a terminal window on the desktop.20Client ApplicationsX Client Arguments, e.g. geometry$ xclock -geometry 100x100-10+10XxY defines size, +X+Y offsetcolor$ xterm -foreground cyan -background black21Networking CapabilityOne can display information from an X client on one computer on an X server running on another. This is useful when you are working on a remote server and need to display all your X applications on your local desktop.on X client specify -displaythis tells client which X server to contact to display its widgets22Networking CapabilityStart xterm on host “eternium”$ xterm -display eternium:0.0:0.0 identifies a displayif the user on eternium has used the xhost command to allow access, then the X terminal window will be displayed on eternium23Networking CapabilityAlternative$ export DISPLAY="eternium:0.0"$ xtermThis is useful when you are working on a remote server and need to display all your X applications on your local