A general architecture for demand migration in a demand-driven execution engine in a heterogeneous and distributed environment

This article is an overview of the GIPSY Demand Migration System (DMS). This system brings a Demand Driven Execution Engine like the one used in the GIPSY to a high level of distributiveness and interoperability of operational nodes, by mixing together advanced distributed technologies. The main Demand Migration System's artifacts are discussed, and their different distributions within the GIPSY are surveyed. The article concludes with a presentation of a successful GIPSY Demand Migration implementation, based on JINI. This paper describes only the aspects of the GIPSY Demand Migration, i.e. it does not deal with load balancing and efficiency aspects of the GIPSY, as these are to be tackled by other subsystems of the GIPSY.