Design and Implementation of Distributed Time Petri-Nets (TPNs) Simulator in the RAS/Tools Framework

The Real-time Architectural Specification (RAS) based on Time Petri-Nets (TPNs) formal method provides a modeling approach to support design and development of reliable real-time distributed systems. In this paper, we present a distributed TPNs simulation algorithm and its clustering implementation for RAS model simulation. The distributed algorithm and implementation can observably simplify the complexity of RAS model structure and improve the performance of system simulation. Two issues focus on the distributed TPNs simulation algorithm: (1) how to get an efficient distributed simulation algorithm of the Time Petri-Nets, and (2) how to design the time agreement of multiple TPNs simulations in distributed system. In addition, we propose a gang schedule strategy that effectively maps multiple simulation threads onto NTcluster. The distributed simulation algorithm, as a core module of the RAS/Tools framework, is implemented by Java class (Jbuilder2.0) and distributed CORBA class (VisiBroker2.0) in an NT workstations-cluster.