This collaborative research grant supports Dr. Timothy Fossum, Professor of Computer Science at the University of Wisconsin-Parkside, to work with colleagues in South Africa and Australia on enhancements to the PC-Xinu operating system. The international partners are Richard J. Foss, Lecturer in Computer Science at Rhodes University, Grahamstown, South Africa; and Christopher Chlap of the Department of Information Sciences and Engineering, University of Canberra, Australia. The research in South Africa will focus on implementing real-time features in PC-Xinu, especially as they relate to control of devices for generating music. A particular emphasis will be Petri net-like real-time synchronization features. The work in Australia will design a dynamic device-allocation mechanism and implement per-process memory protection, to improve on limitations in the current version of PC-Xinu. Extensions to the Xinu system to support new synchronization primitives and new high-speed protocols should enhance the attractiveness of Xinu as a teaching tool, especially for instruction in real-time systems, and in networking. All three research partners have experience in using and extending Xinu. This project promises to strengthen cross-fertilization among ongoing research being conducted by the investigators on three continents.