Integrating Zipcode and PVM: Towards a Higher-Level Message-Passing Environment

This paper describes the architecture and implementation of an integrated message-passing environment consisting of Zipcode and PVM. Zipcode is a highlevel message-passing system for multicomputers and homogeneous networks of computers. PVM is a relatively low-level message-passing system designed for multicomputers and heterogeneous networks of computers. Although PVM provides a workable and easyto-use message-passing system, it does not have some of the high-level constructs, such as communication contexts, required to develop reliable and scalable parallel libraries and large-scale distributed software. By porting Zipcode's high-level constructs on top of PVM, the integrated environment facilitates existing PVM applications to gradually migrate from a low-level to a high-level message-passing paradigm. In the integrated environment described here, Zipcode is ported on top of PVM via an intermediate layer, the emulated Cosmic Environment/Reactive Kernel (CE/RK) layer. Such an integrated environment allows programmers to utilize high-level Zipcode constructs as well as low-level PVM calls. Implementation details of the CE/RK primitives are presented. Planned future enhancements include performance improvement of the integrated system as well as adding heterogeneous environment support.