Distributed Programming with Shared Data

摘要

Operating system primitives (e.g., problem-oriented shared memory, Shared Virtual Memory, the Agora shared memory) and languages (e.g., Concurrent Prolog, Linda, Emerald) for programming distributed systems have been proposed that support the shared variable paradigm without the presence of physical shared memory. The paper looks at the reasons for this evolution, the resemblances and differences among these new proposals, and the key issues in their design and implementation. It turns out that many implementations are based on replication of data. The idea is taken one step further, in a discussion of how automatic replication (initiated by the run-time system) can be used as a basis for a new model, called the shared data-object model, whose semantics are similar to the shared variable model. Finally, the design of a new language for distributed programming--ORCA--is discussed based on the shared data-object model.