%T Distributed Shared Memory in Global Area Networks %A Hans Henrik Happe, Brian Vinter %E Jan F. Broenink, Gerald H. Hilderink %B Communicating Process Architectures 2003 %X Distributed Shared Memory (DSM) has many advantages in heterogeneousenvironments, such as geographically distant clusters or The Grid. These includes:locality utilization and replication transparency. The fact that processes communicateindirectly through memory rather than directly, is giving DSM these advantages.This paper presents the design of Global PastSet (GPS) which is a DSM systemtargeted at global area networks. GPS is based on the DSM system PastSet [1] that hasbeen very effective in homogeneous cluster environments. GPS utilizes consistencycontrol migration and replication to scale in heterogeneous environments. This hasresulted in a token\-based mutual exclusion algorithm that considers locality and analgorithm for locating replicas. GPS has been simulated in multi\-cluster environmentswith up to 2048 nodes with very promising results.