1. Program director for networking at the National Science Foundation's Office of Advanced Scientific Computing, Washington, DC 20550., University College, Dublin, where he is director of the University Computing Service.
2. Professor of computer science at the University of Wisconsin, Madison 53706.
3. Vice president for computing and information technology at Princeton University, Princeton, NJ 08544.
4. Professor of electrical engineering and of computer science at the University of Delaware, Newark 19716.
5. Deputy director of the Division of Computer Research at the National Science Foundation.