Submission to: Conference on Grand Challenges for Computing Research. Grand challenge 4: Ubiquitous Systems

This submission addresses the Ubiquitous Systems Grand Challenge. We propose that the challenge should be more explicit about issues concerning services within such systems. By services, we refer to networked software entities that provide the user with a service. Such services abound in computing and communications: GRID services, information services, network services, voice services, web services, instant messaging, presence and availability services, etc. The services are pervasive, and underpin much of what users see.