The authors thank Ian Goldberg and David Wagner for their contributions to iSpace, NinjaRMI, and the Jukebox application. We would also like to thank all of the graduate and undergraduate students in the Ninja project for agreeing to be guinea pigs for our platform, and Brian Shiratsuki and Keith Sklower for their help in the system of the MultiSpace machines and networks. Finally, we would like to thank our anonymous reviewers and our shepherd, Charles Antonelli, for their insight and suggestions for improvement.