Complementing the role model method with Petri net techniques in studying issues of data freshness of the four-slot mechanism

Simpson’s role model method [7, 8] was designed for the analysis of synchronisationfree data communication mechanisms employing shared memory and has been shown to be especially useful for the representation and analyses of data freshness properties. Previously published analyses using the role model method have employed proprietary state space search techniques developed by Simpson. In this report, a formal definition of role models is given and a way of representing role models using Petri nets is presented. Potential advantages of analysing systems using the role model method complemented with Petri net techniques are demonstrated with a case study of data freshness properties of a data communication algorithm.