Implementing automatic coordination on networks of workstations

Distributed shared objects are a well known approach to achieve independence of the memory model for parallel programming. The illusion of shared (global) objects is a convenient abstraction which leads to ease of programming on both kinds of parallel architectures, shared memory and distributed memory machines. We present several different implementation variants for distributed shared objects on distributed platforms. We have considered these variants while implementing a high level parallel programming model known as coordinators (J. Knopp, 1996). These are global objects coordinating accesses to the encapsulated data according to statically defined access patterns. Coordinators have been implemented on both shared memory multiprocessors and networks of workstations (NOWs). We describe their implementation as distributed shared objects and give basic performance results on a NOW.