Data handles and virtual connections: high-level support for anonymous reconfiguration

Data handles and virtual connections are presented as a solution to the problem of supporting application-driven reconfiguration without sacrificing the separation of communication and computation. The solution supports anonymous reconfiguration, meaning that the module performing the reconfiguration and the modules affected by the reconfiguration need not be aware of each other's presence in the system. The solution allows modules to reconfigure the system within the limits of a specified communication structure while retaining support for dynamic end-user reconfiguration. The work is presented in the context of I/O abstraction, a programming model that defines the communication structure of a distributed system in terms of connections among narrow data interfaces of encapsulated modules. I/O abstraction supports dynamic end-user reconfiguration of distributed applications by separating the communication structure from the module definitions.