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Abstract : |
The OSF Distributed Computing Environment (DCE) is becoming an industry standard for open distributed computing. However, DCE only supports client/server-style applications based on the remote procedure call (RPC) communication model. This paper describes the design and implementation of an extended distributed object-oriented environment, DC++, on top of DCE. As opposed to RPC, it supports a uniform object model, location independent invocation of finegrained objects, remote reference parameter passing, dynamic migration of objects between nodes, and C++ language integration. Moreover, the implementation is fully integrated with DCE, using DCE UUIDs for object identification, DCE threads for interobject concurrency, DCE RPC for remote object invocation, and the DCE Cell Directory Service (CDS) for optional retrieval of objects by name. An additional stub compiler enables automatic generation of C++based object communication interfaces. Low-level parameter encoding is done by DCE RPC?s stub generation facility using the C-based DCE interface definition language (IDL). The system has been fully implemented and tested by implementing an office application. Experiences with the existing system and performance results are also reported in the paper. Furthermore, a former, less transparent implementation of our group using DCE RPC as a pure transportlevel mechanism is compared with the described approach. Related C++ extensions and standardization efforts are also compared with our work. 1, |
