To access nodes of the NIST SP2, outside of the three-node interactive pool,
users must submit their jobs to the batch system, IBM LoadLeveler.
NIST is currently running Version of 1.3 of LoadLeveler.
The commands used to interact with the batch system given below.
For more details on each of these commands, see the local LoadLeveler documentation.
Since both PVM(e) and MPI typically require the user to play an interactive role in the set-up of the parallel environment, a job submitted through Loadleveler must mimic the steps a user would take in an interactive environment. This is accomplished via a shell script, which is invoked when the LoadLeveler job becomes active on the queue. This shell script can be user-defined, but for routine usage, the user may benefit from using prewritten generic scripts. These scripts make use of information provided in the LoadLeveler command file to invoke the appropriate environment control tool (either POE (MPI) or PVM), set the correct number of processors, copy files to/from the local node address space, and start the user's MPMD or SPMD program(s) with the correct arguments and/or input redirection. The scripts do require that certain program information be correctly specified in the LoadLeveler command file, so a user interface has been provided which automates the generation of this command file. This utility is invoked by typing extoll at the Unix prompt in the directory where your executables are stored. (Note that this utility superceeds "X-llcreate" and "llcreate".) The program prompts the user for specific information about the parallel program, and then creates an appropriate command file which includes the appropriate generic script file to properly execute the user program on the nodes. For more information, see the Extoll documentation.