Deductive Verification of Distributed Groupware Systems
Résumé
Replication-based distributed systems consist of a group of users manipulating a shared object (like a text document, a filesystem, ...). Operational Transformation (OT) algorithms are applied for achieving convergence in these systems. However, the design of such algorithms is a difficult and error-prone activity, since building the correct operations for maintaining good convergence properties of the local copies requires examining a large number of situations. In this paper, we present the modelling and deductive verification of OT algorithms with algebraic specifications. We show that many OT algorithms in the litterature do no satisfy convergence properties unlike stated by their authors.