Overview of Distributed Shared Memory

Loosely-coupled distributed systems have evolved using message passing as the main paradigm for sharing information. Other paradigms used in loosely-coupled distributed systems, such as rpc, are usually implemented on top of an underlying message- passing system. On the other hand, in tightly-coupled architectures, such as multi-processor machines, the paradigm is usually based on shared memory with its attractively simple programming model. The shared-memory paradigm has recently been extended for use in more loosely-coupled architectures and is known as distributed shared memory in this context. This chapter discusses some of the issues involved in the design and implementation of such a dsm in loosely-coupled distributed systems and briefly discusses related work in other fields.