Experiences with Asynchronous Communication Models in VEOS, a Distributed Programming Facility for Uniprocessor LANs

Like conventional multiprocessors, workstation clusters can provide data sharing and parallel computing. But unlike multiprocessors, these clusters provide flexible connectivity and can tolerate heterogeneous processing elements. Uniprocessor LANs are a common choice for cost-effective computing. The workstation nodes typically run a version of Unix and support common Unix services such as reliable networking, and multiprogramming. We present VEOS, a highly portable programming facility which effectively utilizes common Unix services for distributed and coarse-grain parallel programs. VEOS was designed for fast prototyping of distributed Virtual Environment applicat ions across heterogeneous workstation clusters. The VEOS programming mode l emphas izes asynchronous communication, and distribution based on entities, a mechanism for non-preemptive task decomposition.