Each node of the SP2 runs the AIX Operating System, IBM's version of UNIX. The SP2 has a Parallel Operating Environment, or POE, which is used for handling parallel tasks running on multiple nodes. (POE will be discussed further in the subsequent section.) The POE also provides a Message Passing Library (MPL), as well as some important tools for debugging, profiling, and system monitoring. These shall also be discussed later. There is software available for system monitoring, and performance profiling and debugging such as the Visualization Tool(VT), prof and gprof profilers, pdbx and xpdbx parallel debuggers. Often, PVM and/or PVMe are/is available on the IBM SP2. Some systems may even have Message Passing Interface(MPI) and/or High Performance FORTRAN(HPF) available. Important math libraries may be available. And, there may be software available to assist you in parallelizing codes such as FORGE90. For more information about what is available on the SP2 you are using can usually be found on the WWW pages for the machine you are using.