Implementing volunteer computing systems involves addressing issues such as programming interface, adaptive parallelism, fault-tolerance, computational security, and scalability, and user interface design. Using Java and HORB, we have designed a flexible object-oriented framework that will allow programmers to experiment with different approaches to these issues by subclassing and composing basic library components.
In this paper, we have shown how this framework is used to implement a particular programming model - master-worker parallelism with eager scheduling, and two different applications - factoring and distributed web-crawling. More work remains to be done on a truly flexible implementation that more easily supports other programming models, but preliminary results give us a positive outlook and hope for success.