From Legion to Legion-G to OGSI.NET: object-based computing for Grids

The object abstraction has long proven to be an effective foundation upon which to structure application codes; however, its application to Grid Computing contains many challenges related to the heterogeneous, dynamic, and cross-administrative-domain nature of Grids. This paper contains an overview of the succession of three projects at the University of Virginia that provide object-based support for Grid computing: Legion, Legion-G, and OGSI.NET. Throughout the three projects, the overall goal has remained to reduce the barrier for entry to Grid applications developers, thereby enabling next-generation Grid applications beyond those that have been provided by today\´s "heroic programmers". The successes of each project with respect to this overall goal are discussed.