Casper: A Cached Architecture Supporting Persistence

Persistent object systems greatly simplify programming tasks since they hide the traditional distinction between short-term and long-term storage from the applications programmer. As a result, the programmer can operate at a level of abstraction in which short-term and long-term data are treated uniformly. It is important that such a persistent system be capable of being used concurrently; such concurrent usage may arise because of parallel process facilities in the programming language concerned, or because of multiple users of the same persistent store. Concurrent access has not been satisfactorily supported in existing persistent store implementations and a number of significant research issues remain to be investigated. This paper describes an architecture that supports concurrent access to a shared persistent object store. The persistent distributed architecture represented by our system exploits a number of the facilities provided by the Mach distributed operating system