DRASTIC: A Run-Time Architecture for Evolving, Distributed, Persistent Systems

Modern systems must be adaptable | to changing requirements, bugxes, new technologies and recon guration. For critical applications this must be possible at run-time; for complex applications it should be limitable to major sub-divisions of the system. The DRASTIC architecture addresses these goals by exploiting object persistence and distributed systems implementation techniques. It enables run-time changes of types, implementations, and the system con guration. This is based on a novel architectural abstraction of locality for evolution, called the `zone'. Contracts between zones automatically limit the visibility of such changes between zones. We present work in progress on DRASTIC's computational model and run-time system, illustrating support for software evolution and highlighting key features of our current implementation. A slightly shorter version of this paper appears in the ECOOP'97 conference proceedings. This document contains more information on the DRASTIC implementation details and related work. This paper will appear shortly as a Glasgow University, Department of Computing Science Technical Report.