The Pilgrim: A New Consistency Protocol for Distributed Shared Memory

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 the DSM to allow programmers to share objects or variables without having to manage the exchange. We present an algorithm which uses the token technique. The token is data structure which contains the updates of shared data. These data are carried through the ring on the token, named Pilgrim. Pilgrim protocol provides both reliable consistency and guaranteed performance according to the type of application described. The protocol is discussed and proved, and we demonstrate its qualities. Key words: consistency protocol, cooperative work, distributed shared memory, virtual ring. 1 Introduction In this paper, we propose a new consistency protocol for distributed shared memory (DSM) where different shared objects are replicated at eac..