The Processing Graph Method Tool (PGMT)

To acquire state-of-the-art hardware at reduced cost, the U.S. Navy is committed to buying Commercial Off The Shelf (COTS) computer hardware. In this rapidly changing technological world, today's hardware will be obsolete tomorrow. The Navy's complex problems often require more computational power than can be delivered by a single serial processor. The solution lies in distributed processing. However, distributed processors tend to have architecture specific languages, requiring an expensive and time-consuming manual rewrite of application software as new technology and new machines become available. The Processing Graph Method (PGM), developed at the Naval Research Laboratory (NRL) in Washington, DC, is an architecture independent method for specifying application software for distributed architectures. Its model of computation is reconfigurable dynamic data flow: dynamic, because the amount of data consumed and produced by an actor may vary from one firing to another; and reconfigurable, because a graph may be disassembled and reassembled. PGM was implemented on the Navy Standard Signal Processor (AN/UYS-2), and on VAX and Sun workstations. The PGMT project at NRL is developing a tool set that will facilitate the implementation of PGM on a given distributed architecture at relatively low cost. We describe the major features PGM and discuss the PGMT project.