Shared memory multimicroprocessor operating system with an extended Petri net model

We propose a methodology for programming multiprocessor event-driven systems. This methodology is based on two programming levels: the task level, which involves programming the basic actions that may be executed in the system as units with a single control thread; and the job level, on which parallel programs to be executed by the complete multiprocessor system are developed. We also present the structure and implementation of an operating system designed as the programming support for software development under the proposed methodology. The model that has been chosen for the representation of the system software is based on an extended Petri net, which provides a well-established conceptual model for the development of the tasks, thus allowing a totally independent and generic development. This model also facilitates job-level programming, since the Petri net is a very powerful description tool for the parallel program