The Plan B OS for ubiquitous computing. Voice control, security, and terminals as case studies

The conventional approach to building pervasive environments relies on middleware to integrate different systems. Instead, we have built a system that can deal with these environments by exporting system resources through distributed virtual file systems. This requires no middleware, simplifies interoperation, and permits the application of general purpose tools to any system resource. A constraint-based file system import mechanism allows the system to adapt to changes in the environment and permits users to customize the environment and tailor adaptations according to their needs. The system has been in use for over a year to carry out our daily work and is underlying the smart space that we built for our department. The system, and some novel services, including ubiquitous voice interfaces, a distributed security architecture, and remote terminals for smart spaces, are also described in this paper.