Paper: Parallel Tree N-body Code: Data Distribution and DLB on the CRAY T3D for Large Simulations Volume: 145, Astronomical Data Analysis Software and Systems VII Page: 7 Authors: Becciani, U.; Antonuccio-Delogu, V.; Gambera, M.; Pagliaro, A.; Ansaloni, R.; Erbacci, G. Abstract: We describe a strategy for optimal memory and work distribution. We have performed a series of tests to find an {\it optimal data distribution} in the Cray T3D memory, and to identify a strategy for the {\it Dynamic Load Balance} (DLB). The results of tests show that the step duration depends on two main factors: the data locality and the network contention. In a very large simulation, due to network contention, an unbalanced load arises. To remedy this we have devised an automatic work redistribution mechanism which provided a good DLB.