Technical Briefs

ROHAN help Files

xwindows

Xwindows is a graphics and windowing system designed to operate over a network. There are two parts, a client and a server which communicate using the X Protocol. Unlike a personal computer, which runs applications locally, the applications are actually run off the server and displayed locally on the user's screen.

Xwindows divides up the user's screen into multiple windows, each able to run a separate application. The windows can either run programs that have a point-and-click, graphical interface, or they can emulate a terminal allowing a workstation to display multiple, simultaneous terminal sessions.

Running X Applications Remotely

If you are running X Windows on a Unix computer other than the one you originally logged onto (ie: remotely accessing Rohan from another Unix computer), you should use ssh to connect to Rohan. The ssh (Secure Shell) program will set your DISPLAY variable so X applications can be viewed. Telnet and rlogin will not.

If you can not use ssh, you must reset the DISPLAY variable on the remote machine to that of the machine you are logged onto. You can determine the value of the local DISPLAY variable by typing,

   echo $DISPLAY

Then set your local machine to allow the display from the remote machine with the command,

   xhost +remote.sdsu.edu

Finally, once you are logged onto the remote machine on which you will run the X application, type,

   setenv DISPLAY machine.sdsu.edu:0.0

where machine.sdsu.edu is the value returned by the echo command.