Amar Bouali

We describe a set of modular extensions to our Auto/Graph veriication toolset for networks of communicating processes. These software additions operate from a common le exchange format for automata and networks, called fc2. Tool functionalities comprise graphical depiction of objects, global model construction from hierarchical descriptions, varr ious types of model reductions and of veriication of simple modal properties by observers, counterexample production and visualisation. We illustrate typical veriication sessions conn ducted on usual academic examples: dining philosophers, mutual exclusion algorithms and round-robin schedulers. Based on previous experience of drastic state explosion problems we aim here at eeciency in implementation. We use both explicit representation techniques and implicit techniques such as BDDs, with functional overlap at places. RRsumm : On ddcrit un ensemble d'extensions modulaires nos systtmes Auto/Graph de vriication des rrseaux de processus communicants. Ces nouveaux logiciels oprent sur la base d'un format commun d''change pour les automates et les rrseaux, appell fc2. Les fonctionnalitts de ces outils comprennent la description graphique d'objets, la construction de moddle global depuis des description hiirarchiques, plusieurs types de rrductions de moddle et de vriication de propriitts modales simples par observateurs, la production et la visualisation de contre-exemples. On illustre des sessions de vriication conduites sur des exemples acaddmiques classiques: le probllme du ddner des philosophes, des algorithmes d'exclusion mutuels et les schedulers round-robinn. Bass sur les expriences prrccdentes se heurtant au probllme de l'explosion de l'espace d''tats, nous avons pour but ici une implantation eecace. Nous utilisons deux modes de reprrsentation, explicite et implicite par BDDs, en ayant une redondance des fonctionnalitts dans chaque mode. Systems of communicating and synchronising entities are usually hard to specify in a correct fashion, due to problems of distributed control and parallelism. In the last decade a number of veriication softwares were implemented to provide computer assistance in the design and correctness checking of such system descriptions, and used to study distributed algorithms, protocols and embedded systems. Most commonly these toolsets are based on nite state modeling of underlying global conngurations, and graph-theoretic algorithms. Our pioneering Auto/Graph toolset was exploring the power of so-called proof-byre -ductionn techniques, where methods for compositional reductions of nite state structures try to suppress as much as possible the combinatorial explosion problem. Functions such as state quotient (with respect to behavioural equivalences), behavioural abstraction or context ltering were at the heart of the system, in addition to graphical or textual process …