A SUITE OF DEFINITIONS FOR CONSISTENCY CRITERIA IN DISTRIBUTED SHAREDMEMORIES

A shared memory built on top of a distributed system constitutes a dis tributed shared memory (DSM). If a lot of protocols implementing DSMS in various contexts have been proposed, no set of homogeneous definiti ons has been given for the many semantics offered by these implementat ions. This paper provides a suite of such definitions for atomic, sequ ential, causal, PRAM and a few others consistency criteria. These defi nitions are based on a unique framework : a parallel computation is de fined as a partial order on the set of read and write operations invok ed by processes, and a consistency criterion is defined as a constrain t on this partial order. Such an approach provides a simple classifica tion of consistency criteria, from the more to the less constrained on e. This paper cart also be considered as a survey on consistency crite ria for DSMS.