Petri Nets

• Purpose: Model Concurrent Systems & Synchronization

(Asynchronous Model: No Time)

• Definition of a Petri Net:

{ Places, Transitions, Inputs to Transitions, Outputs from Transitions}

 

• Tokens , Marking, and State

• Execution of a Petri Net: Enabled Transitions

Firing a Transition

• Example: Modelling a Simple Computer System

• Resource Sharing and the Critical Section Problem

(from the Text)

• Starvation and Deadlock

-- Limitations : Expressiveness, Convenience

-- Extensions : Token Data, Transition Guards and Functions