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network, as are the processors within each site. The negligible intrasite communication costs and significant intersite communication costs define the boundaries for each site. This requires a scheme that addresses effective distribution across as well as within each site. Our proposals deal with both. Devising such a scheme to optimize meaningful design criteria is a complex problem that requires a pragmatic and opportunistic approach and demands substantial changes to the way we think about object technology. The proposed scheme exploits relevant features of OO systems and extends current data distribution research to (a) identify and formalize appropriate design criteria and (b) develop techniques for optimization of these criteria. We outline the issues faced, the pragmatic decisions required, and the solution mechanisms developed to realize the distribution scheme. We do not discuss technical details of …