The advantages of distributed shared memory have made it the focus of recent study and have prompted the development of various algorithms for implementing the shared data model. Several implementations have demonstrated that, in terms of performance, distributed shared memory can compete with direct use of data passing in loosely coupled distributed systems.
The algorithms described can be categorized by whether they migrate and / or replicate data, as depicted in figure below. Two of the algorithms migrate data to the site where it is accessed in an attempt to exploit locality in data accesses and decrease the number of remote accesses, thus avoiding communication overhead. The two other algorithms replicate data so that multiple read accesses can take place at the same time using local accesses.
The Read-Replication Algorithm
The Full-Replication Algorithm
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