Huw Evans

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This paper describes a novel approach to managing the evolution of distributed, persistent systems at run-time. This is achieved by partitioning a system into disjoint <italic>zones</italic>, each of which can be evolved without affecting code in any other. <italic>Contracts</italic> are defined between zones, making type-level interdependencies and(More)
Modern systems must be adaptable | to changing requirements, bug-xes, new technologies and reconnguration. For critical applications this must be possible at run-time; for complex applications it should be limitable to major subdivisions of the system. The DRASTIC architecture addresses these goals by exploiting object persistence and distributed systems(More)
Providing infrastructural support for pervasive computing environments is difficult due to their ever changing, resource-limited nature. In such environments, generative communications would be of benefit due to the decou-pling the paradigm offers. This paper introduces Tiamat, a system which provides a coordination infrastructure for applications in(More)
This paper describes the experience of porting a 25,000 line distributed Java [GM96] program to version of the orthogonally persistent programming environment PJama. The port was performed in two stages. The first stage, changing the source code, took two days. The second stage, ensuring the ported program exhibited a suitable run-time behaviour,(More)
This position paper describes the Grumps approach to the on-line upgrading of objects in a distributed system. This is supported by three main, well-known ideas: core code abstractions are defined in terms of Java interfaces and not classes; as many decisions as possible are delayed until run-time; and object containers are used to manage groups of objects(More)