UNIX/IRAF Site Manager's Guide

4.4. Using the workstation with a remote compute server

A common mode of operation with a workstation is to run IRAF under a window system directly on the workstation which runs IRAF, accessing files either on a local disk, or on a remote disk via a network interface (NFS, IRAFKS, etc.). It is also possible, however, to run the window system on the workstation, but run IRAF on a remote node, e.g., some powerful compute server such as a large UNIX server, a large VAX, vector minisupercomputer, supercomputer, etc., possibly quite some distance away. This is done by logging onto the workstation, starting up the window system, logging onto the remote machine with rlogin, telnet, or whatever, and starting up IRAF on the remote node.

If X11 is running on the local workstation as well as on the remote system, and one's favorite X11 client it installed on the remote system, then the networking support built into X11 can be used to display and plot remotely. This is not always possible however. If the necessary X11 clients are not available on the remote system or the networking connection does not support X11, it is still possible to work remotely using the networking capabilities built into IRAF, provided one is already running IRAF on the remote node.

After IRAF comes up one need only type

cl> stty xterm
cl> reset node = hostname!

to tell the remote IRAF that it is talking to an xterm window (for example) and that the image display is on the network node hostname. The trailing exclamation point is required in V2.10.4 and later versions of IRAF to avoid interpretation of general environment variables as network logical node names.

In this mode one is effectively using the workstation as a sort of super terminal with powerful graphics and image display capabilities. One gets the best of both worlds, i.e., a state of the art user interface, and the compute power of a large machine. It matters little what operating system is used on the remote machine, so long as it also runs IRAF. Except for the details of the login sequence, operation is completely transparent; xgterm does not care whether the process it is talking to is on a local or remote node. Performance, e.g,. for image loads, is often better than when everything is run directly on the local node, due to the more powerful server.