The PEG environment: parallel programming with Petri net semantics

The author discusses PFG (parallel flow graphs), a hardware/software system modeling language and support environment based on a concurrent, place-timed deterministic Petri net formalism termed the HG (hierarchical graph) model of time-dependent concurrent systems. The HG model serves as the formal semantics of computation for the PFG language, which has a graphical syntax and serves as a composition vehicle for Petri nets that have interpretable form and limited complexity. The PFG environment is a collection of cooperating tools that operate on these HG models for the production of reliable time-dependent software systems from reusable components. Algorithms that have been developed for analysis of the HG formalism include detection and correction of improper access to shared data, calculation of minimum and maximum execution time bounds, and matching of models to graphical specification templates for reuse.<>