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X Window System. The X Window System The graphical environment for Linux is not a core part of the operating system. Rather, it is a service provided by a running process much like a Web server GUI infrastructure for UNIX and Linux systems • Created in 1984
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The X Window System The graphical environment for Linux is not a core part of the operating system. Rather, it is a service provided by a running process much like a Web server GUI infrastructure for UNIX and Linux systems • Created in 1984 • Both a Protocol and an Implementation Advantages of X • Operating System Independent • Modular and Extensible • Client-server (Network Transparent!) XFree86 • Original Free Open Source implementation of the X Window System X.Org • Forked XFree86 with a more open development model
X.Org Drivers Binary modules (drivers) for different video chipsets • Drivers, in theory, are platform-neutral Advanced features such as 3D acceleration are supported Drivers for most newer video cards are available Some features require proprietary drivers
Starting X • X already running in runlevel 5 with a graphical login • From a text virtual terminal login, use startx • • startx is a shell script that eventually runs xinit • • can run xinit manually, but all that gets started is an X server
X Access Control • xhost • The xhost command can be used to control host-based access control. • $ xhost +bar.example.com • # bar.example.com can access the server • $ xhost + • # anyone can access the server • $ xhost - • # bar.example.com can still access the server • $ xhost -bar.example.com • # bar.example.com cant access the server
Insecure Remote X On the Local System - Determine Display Name On the Remote System - export DISPLAY of2 $ hostname of2.orafact.com of2 $ echo $DISPLAY :0.0 of2 $ telnet of4.orafact.com Trying 192.168.1.4... Connected to of2.orafact.com (192.168.1.4 ) . . . snip . . . login: guest Password: welcome of4 $ export DISPLAY=of2.orafact.com:0 of4 $ xclock
Alternative Remote Graphical Protocols VNC • Cross-platform • Open source can be found at http://www.realvnc.com/.