Implementation and evaluation of distributed shared data objects on a workstation cluster

We are developing a system called KaReN to handle distributed shared data objects on workstations that are connected by Ethernet. The system supplies users with a parallel programming environment of virtually shared data objects. The KaReN was developed using the message passing library PVM (parallel virtual machine) to have good portability. To reduce the overhead in maintaining data coherence, several methods are introduced. Request merging is introduced to reduce the message traffic. The copy transfer messages are also clumped when possible. The weak consistency is another optimization for eliminating unnecessary coherence control messages by allowing a temporally inconsistent state. This paper presents the organization and the implementation of the KaReN. Several applications have been executed for the system evaluation.