Design of a heterogeneous DSM system with distributed objects

Parallel processing platforms in general can be classified into DSM (distributed shared memory) and message-passing systems. DSMs provide a simpler programming interface compared to the latter. For DSMs, memory latency reduction and heterogeneity support have been major research areas. Among the research systems, Java/DSM is one that succeeded in shielding hardware differences completely from the programmers. However, its underlying hardware dependent page-based DSM imposes constraints on the portability of the system. To eliminate such a limitation, we designed and implemented a DSM system completely in distributed objects. The distributed object middleware utilized shields hardware and operating system differences from the programmers, while also furnishing the system with language independence capability and providing much wider platform support, leading to a higher degree of portability and heterogeneity. The system is relaxed consistent. This paper provides a detailed description of its consistency properties and the protocols used to achieve them.