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Adaptable Dependable Wrappers

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Final rept. Sep 96-Jun 99

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The objective of the Adaptable Dependable Wrappers effort was to design and implement tools that facilitate the creation of specialized wrappers for software components of a distributed system. The affordable upgrading of systems requires better technology than currently available to support evolutionary adaptation through incremental change. Support is needed for distributed systems so that incremental changes may be applied routinely and inexpensively. This support must allow incorporation of new code into running systems and diffusion of new code throughout distributed subsystems automatic analysis of new code to identify its worst case behavior and interference with existing code fine grained control over privilege given to new code protocols to coordinate the diffusion of new code replacement of protocol layers without disruption to processing in other protocol layers and protocols to tolerate and adapt to subsystem failures. Much of the technology needed for evolutionary computing can be localized in software wrappers. Software wrappers are often used to glue existing subsystems into a larger system with new properties and functions. A wrapper is a software layer used to change the interface of a component or to give new properties, such as fault tolerance or security to the interaction between components. By changing the wrappers, component interfaces can be changed to allow new connections between components. Properties can be changed to satisfy new requirements. These changes permit much of the flexibility that evolutionary computer systems need. This report describes an investigation into tools which support the creations of such wrappers.

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  • Computer Systems

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