such X nesting. Remote desktop To run an X client application on a remote machine, the user may do the following: on the local machine, open a terminal window use command to connect to the remote machine request a local display/input service (e.g., export DISPLAY=[user's machine]:0 if not using SSH with X forwarding enabled) The remote X client application will then make a connection to the user's local X server, providing display and input to the user. Alternatively, the local machine may run a small program that connects to the remote machine and starts the client application. Practical examples of remote clients include: administering a remote machine graphically (similar to using remote desktop, but with single windows) using a client application to join with large numbers of other terminal users in collaborative workgroups running a computationally intensive simulation on a remote machine and displaying the results on a local desktop machine running graphical software on several machines at once, controlled by a single display, keyboard and mouse User interfaces X primarily defines protocol and graphics primitivesit deliberately contains no specification for application user-interface design, such as button, menu, or window title-bar styles. Instead, application softwaresuch as window managers, GUI widget toolkits and desktop environments, or application-specific graphical user interfacesdefine and provide such details. As a result, there is no typical X interface and several different desktop environments have become popular among users. A window manager controls the placement and appearance of application windows. This may result in desktop interfaces reminiscent of those of Microsoft Windows or of the Apple Macintosh (examples include GNOME 2, KDE, Xfce) or have radically different controls (such as a tiling window manager, like wmii or Ratpoison). Some interfaces such as Sugar or ChromeOS eschew the desktop metaphor altogether, simplifying their interfaces for specialized applications. Window managers range in sophistication and complexity from the bare-bones (e.g., twm, the basic window manager supplied with X, or evilwm, an extremely light window manager) to the more comprehensive desktop environments such as Enlightenment and even to application-specific window managers for vertical markets such as point-of-sale. Many users use X with a desktop environment, which, aside from the window manager, includes various applications using a consistent user interface. Popular desktop environments include GNOME, KDE Plasma and Xfce. The UNIX 98 standard environment is the Common Desktop Environment (CDE). The freedesktop.org initiative addresses interoperability between desktops and the components needed for