On the integration of concurrency, distribution and persistence

Abstract

The principal tenet of the persistence model is that it abstracts over all the physical properties of data such as how long it is stored, where it is stored, how it is stored, what form it is kept in and who is using it. Experience with programming systems which support orthogonal persistence has shown that the simpler semantics and reduced complexity can often lead to a significant reduction in software production costs. Persistent systems are relatively new and it is not yet clear which of the many models of concurrency and distribution best suit the persistence paradigm. Previous work in this area has tended to build one chosen model into the system which may then only be applicable to a particular set of problems. This thesis challenges the orthodoxy by designing a persistent framework in which all models of concurrency and distribution can be integrated in an add-on fashion. The provision of such a framework is complicated by a tension between the conceptual ideas of persistence and the intrinsics of concurrency and distribution. The approach taken is to integrate the spectra of concurrency and distribution abstractions into the persistence model in a manner that does not prevent the user from being able to reason about program behaviour. As examples of the reference model a number of different styles of concurrency and distribution have been designed and incorporated into the persistent programming system Napier88. A detailed treatment of these models and their implementations is given.