A new consistency protocol implemented in the CAliF system

We propose a new consistency protocol for distributed shared memory (DSM) where different shared objects are replicated at each site. This protocol was developed for the cooperative platform called CAliF: Cooperative Application Framework. This system uses DSM to transparently handle the data sharing. We present an algorithm which uses the token technique. Updates of shared data are carried through a virtual ring on the token, named Pilgrim. The Pilgrim protocol provides both reliable consistency and guaranteed performance according to the type of application described. The protocol is described, proved and then simulated using the SPIN model checker and we demonstrate its qualities