Petri-Net Implementation of Recovery Strategies in a Large ESS

A practical experience of design with Petri-nets is described, which basically consists in the analysis and implementation of recovery strategies within the project of a large stored program controlled electronic switching system.Emphasis is put on the optimum adequacy of Petri-nets for the analysis and representation of all fault-tolerance related phenomena.Net tailoring and adaptation to the peculiar application is also briefly discussed together with a short outline of the interactive design aids specially developed for this purpose.A summary of unsolved or still open problems, all of which are currently under study concludes the presentation.