A two-level programming strategy for distributed systems

In this paper we present a global approach for programming distributed multiprocessor systems. In this approach, applications are developed as a global parallel program that is independent of the particular hardware architecture, and is represented through an extended Petri net model. The building blocks for the global program are tasks that are implemented using standard programming languages. A highly automated tool is used to allocate the different tasks to processing nodes in a near-optimum way, minimizing message traffic in the interconnection network and balancing the execution workload in the different nodes. The combined use of this tool with analysis and simulation tools for Petri nets allows us to obtain information about the performance and behavior of the global program. The tool divides the original extended Petri net into several subnets that are distributed among the different nodes, and provides for the installation, execution, and monitoring of the program. An example is presented in which our programming strategy is compared to PVM, which is a widely extended software tool for the distribution of programs in a network of computers.