Persistent objects in the Fleet system

Fleet is a middleware system implementing a distributed repository for persistent Java objects. Fleet is primarily targeted for supporting highly critical applications: in particular, the objects it stores maintain correct semantics despite the arbitrary failure (including hostile corruption) of a limited number of Fleet servers and, for some object types, of clients allowed to invoke methods on those objects. Fleet is designed to be highly available, dynamically extensible with new object types, and scalable to large numbers of servers and clients. In this paper, we describe the design of Fleet objects, including how new objects are introduced into the system, how they are named, and their default semantics.