who may use an external physical display in addition to the computer's built-in screen, but only at certain locations. It is recommended that RandR or ATI's or nVidia's single GPU method be used in these cases. Xinerama's lack of support for adding or removing screens causes several problems: Windows may be drawn to a screen that is not connected to the computer. The user is required to drag these windows to the main screen, but is unable to see them. Video signals sent to disconnected displays use unnecessary power and may reduce battery life. It becomes difficult to use a device in multiple locations, where available external screens are likely to be configured differently. These problems are related to Xinerama's implementation rather than its design, and can be corrected with further development. Window manager support Some window managers and desktop environments have limited awareness of the separate physical screens in Xinerama, so that the desktop is simply stretched over the physical screens instead of arranged as a single large desktop. The window manager may place a new window on an unexpected screen, which can be confusing and annoying. Xinerama nevertheless offers the advantage that windows can be moved between screens. Dead space The physical displays do not need to be the same resolution, and the virtual display area is not necessarily rectangular if the component physical displays are not the same size. Some window managers assume a rectangular display area, and enforce this by creating excess "dead space" at the edges of a display. The window manager needs awareness of Xinerama to avoid placing new windows in this dead space. See also Multi-monitor Resource Asmus, Madeline T. (December 1995) "The PanoramiX Extension" THE X RESOURCE 16: A Practical Journal of the X Window System. pp. 59–73 . Notes References Overview of X11R6.8 (X.Org) External links Using Xinerama to MultiHead XFree86 V. 4.0+ - HOWTO from The Linux Documentation Project. Using multiple monitors with XFree86 - Simple configuration examples. Freedesktop.org Multi-monitor X Window extensions