9421935 Kedem This award is to purchase a small network of workstations with accessories and software to support 4 research projects: 1) Further development of Calypso, a software-based execution platform for high-performance computing. This experimental project grew out of previous theoretical work dealing with abstract machines. The current prototype will be further enhanced and tested on selected applications. Special attention will be paid to scalability, load balancing, and fault tolerance. 2) Experimentation with Persistent Linda, an implementation of a fault-tolerant Linda built on top of lightweight transactions. Large-scale experimentation will be conducted using multiple machines executing long-running parallel computations. 3) Construction of an experimental platform for the easy implementation and evaluation of fundamental, symbolic computation algorithms. Special attention will be given to making the platform robust, flexible, and portable. 4) Distributed extension to a novel, centralized persistent object system will be developed. The system will be enhanced by new facilities such as type security, distributed locking, distributed synchronization, and collaborative applications. ***