A Characterization of Scalable Shared Memories

The traditional consistency requirements of shared memory are expensive to provide both in large scale multiprocessor systems and in distributed systems that implement a shared memory abstraction. As a result, several memory systems have been proposed that enhance performance and scalabil ity by providing weaker consistency. The differing models used to describe such memories make it difficult to relate and compare them. We develop a simple non-operational model and identify parameters that can be varied to de scribe existing memories and to identify new ones. We show how a uniform framework makes it easy to compare and relate various memories.