Project: Verification of Complex Hierarchical Systems (VOCHS)

The Compact Muon Solenoid (CMS) research group at CERN is responsible for one of the four experiments in the Large Hadron Collider in Geneva. The software, controlling this experiment, consists of 20,000 finite state machines, which are strictly hierarchically organised. The complexity of the software has grown out of hand and it is not predictable anymore. This is becoming a nuisance. Consequently, the CMS research group currently invests in the verification thereof by translating the finite state machines to mCRL2, which is a behavioural specification and analysis methodolgy which we have developed. Verification of small constellations of state machines is quite straightforward. However, the verification of the entire system consisting of 20,000 parallel components is of a different category, which cannot be done by CERN alone, but requires our skill and experience. We are convinced that the hierarchical architecture enables us to prove the correctness of this massive control system. As the Large Hadron Collider will become fully operational in the coming years, an urge is felt to get the software right. In tackling this problem, we pursue two main approaches concurrently. The first approach is to employ (symbolic) PBES technology that we have developed for the verification of modal properties. Our second approach is to employ the sheer power of parallel processing using (distributed clusters of) multi-core cpus for solving BESs resulting from modularised PBESs. This project is geared towards the verification challenge at CERN; its underlying purpose is to increase the verification capabilities as a whole.