Sun/IRAF V2.11 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 Sun/IRAF under OpenWindows 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 OpenWindows with xgterm and ximtool on the workstation, but run IRAF on a remote node, e.g., some powerful compute server such as a large Sun server, a large VAX, or a vector minisupercomputer or supercomputer, possibly quite some distance away. This is done by logging onto the workstation, starting up OpenWindows and a xgterm window, logging onto the remote machine with rlogin, telnet, or whatever, and starting up IRAF on the remote node.

After IRAF comes up one need only type

cl> stty xgterm
cl> reset node = hostname!

to tell the remote IRAF that it is talking to a xgterm window 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. For this to work IRAF networking must be enabled between the two hosts (see §2.2.7). Alternatively, an inet socket may be used to connect to the ximtool directly by defining an IMTDEV environment variable. For example, suppose you are running IRAF on remote node but wish to display to an ximtool running on your workstation which is in a different network domain, to do this define something like

% setenv IMTDEV	inet:5137:foo.bar.edu

prior to logging into the CL. This overrides the normal display connection selection and tells IRAF to display to inet socket 5137 running on node "foo.bar.edu" (5137 is the default inet socket for ximtool). The advantage here is that one doesn't need to enable iraf networking for a host that may only temporarily be used.

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.