Architecture of a light-weight non-threaded event oriented workflow engine

The architecture of a thin distributed event-oriented non-threaded but concurrent workflow engine is presented. The approach shows how to architecture a non-threaded workflow engine by eliminating threading through event-oriented paradigm without degrading performance. The architecture is presented formally in terms of just a handful of expressions in CCS, the Calculus of Communicating Systems. The CCS based light-weight model of the distributed engine is built keeping in mind the separation of the outer layer of events with implementation, extensibility, and also the issue of traceability into implementation. The engine with all its components has been implemented over TAO realization of CORBA utilizing its event service component. Performance results of the implementation are also provided including a comparison to a popular open-source workflow system.