It is possible to run graphics applications on helix and have the graphics display on your desktop machine (Unix workstation, Mac or PC). The Unix X-windows system is designed for just this purpose. All Unix workstations are capable of X-windows display by default, but Mac/PC users will need to install an X-windows emulator. We provide free X-windows emulation software (Mac and PC) for Helix users.

PCs

X-Win32 is the only PC X server that lets you connect to multiple UNIX/Linux desktops at the same time and also run some X Windows applications in separate Xterm windows. It is also easy to install, configure and operate. Installation includes integrated secure shell (SSH). You will need to download it from the helix website and install it on your machine.

Download/Installation instructions for X-Win32

Macs

Mac X11 for Mac OS X offers a complete X Window System implementation for running X11-based applications on Mac OS X. Based on the de facto-standard for X11, the open source XFree86 project, X11 for Mac OS X is compatible, fast and fully integrated with Mac OS X. Mac X11 is usually installed by default when Mac OS X is installed. You need Mac OS version 10.3 or up to use X11 for Mac.

Get X11 for Mac OS X (in case it was not installed by default).

(http://www.apple.com/support/downloads/x11formacosx.html)

Detailed instructions for opening an ssh/X-Windows session with Mac X11. Once you have Mac X11 installed, you can open an X terminal window on Helix. Any X application can now be launched by typing its name after the Helix prompt.

Unix workstations

Unix workstations (SGIs, Suns, Linux machines etc.) include X windows software by default. In a terminal window on your desktop machine, type

ssh -X username@helix.nih.gov

to tunnel your X-Windows connection through the ssh connection. Log in to Helix with your password. You should now have an X-Windows connection to Helix.

Unix Troubleshooting

1. Type 'echo $DISPLAY' on your workstation. You should see something like 'machinename.nih.gov:0.0', or sometimes just ':0.0'. If your DISPLAY variable does not appear to be set, type 'setenv DISPLAY :0.0' (csh) or 'DISPLAY=:0.0; export DISPLAY' (bash).
2. Type 'xclock' on your local machine to make sure that you have X running. If you don't see an xclock appear, start up X on your desktop machine.
3. Type 'echo $DISPLAY' on Helix. You should see something like 'helix.nih.gov:12.0'. If the DISPLAY variable does not appear to be set on Helix, your ssh/Xwindows tunnel did not work. Log out of Helix and reconnect with 'ssh -X username@helix.nih.gov'.
4. Type 'xclock' on Helix. You should see an xclock appear on your workstation desktop. If you don't see this, and the previous steps worked correctly, contact the Helix staff at staff@helix.nih.gov or 301-496-4357.