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X-windows

Many Unix and Linux programs require X-windows for graphical output. These programs require an X-windows server or X-server to be running on your workstation. An X-server is included with all modern Unix and Linux distributions. A download version for MS-Windows is available from http://www.LabF.com which allows 30 minute sessions without registration. HPCC has some licensed versions of X-Win32, please inquire for availability. A free X-server, XWin, is packaged with the Unix environment for Windows, cygwin.

X-windows requires you to tell the host (the remote computer) where the display workstation is and requires the display workstation to give the host permission to display on it.

To tell hrothgar/weland where your workstation is, run on your workstation:
hostname on Unix/Linux or
ipconfig or winipcfg on MS-windows
to get either your workstation's IP alias such as mycomp.alchemy.ttu.edu or its numeric IP address such as 129.118.33.1 . The alias and numeric address may be used equivalently if name services are working properly on your network; if you have a problem try the numeric address. If you are remotely logged into a SGI computer using ssh, it may be more convenient to run in the ssh window:
printenv | grep SSH_CLIENT and use the first of three numbers reported:
SSH_CLIENT=129.118.33.1 1076 22 is IP address 129.118.33.1 .

On hrothgar/weland, after logging in with SSH, enter, replacing with your actual workstation name or numeric IP address:

csh: setenv DISPLAY mycomp.alchemy.ttu.edu:0.0
bash: export DISPLAY=mycomp.alchemy.ttu.edu:0.0

Start the X-server on your workstation if necessary. If you are using Cgywin Xwin on your pc, start a Cygwin bash shell from a DOS command shell:
cygwin
Then set DISPLAY:
export DISPLAY=mycomp.alchemy.ttu.edu:0.0
Cygwin is an exception to other PC X-servers in that DISPLAY needs to be set on both the host and the display workstation. Then set in the Cygwin shell
xhost +
And start the Xserver:
XWin &
In our experience, qualifiers to xhost such as: xhost + 129.118.104.4
do not work well on Cygwin and will deny access.

Since it is inherently insecure, please do not run X display manager (xdm) remotely from HPCC hosts.

In some locations, your workstation may be behind a firewall from the HPCC computers. If you have trouble with Xwindows connections, try tunneling. Set up the initial window (on Unix/Linux):

ssh -X hrothgar.hpcc.ttu.edu

MS-windows X-servers should have an equivalent command. Tunneling sends the Xwindows communications disguised as ssh communication. If using tunneling, do not setenv DISPLAY as it will be set to the correct value by the ssh connection. You should also remove any DISPLAY commands from files such as .login or .bashrc .