How the "What" Becomes the "How"

Summary form only given. There have been growing interest in pervasive computing environments. Peppered with wireless, mobile and embedded devices, such environments are characterized by a degree of dynamism not common in traditional distributed systems. A fundamental problem highlighted by such emerging environments is how to satisfy and sustain an application´s service requirements in the face of continuous changes in available resources. An application in such an environment cannot be programmed to depend on a predetermined set of resources to access a service. Rather, resources must be dynamically discovered and opportunistically utilized to sustain the application´s service requirements in its changing environment. In this talk, the author describe three systems, developed as part of Project Oxygen at MIT, that take different approaches to opportunistic service access. The first system, intentional naming system (INS, SOSP´01), integrates adaptive service access with the network routing layer. The second architecture, dubbed service-oriented network sockets (SoNS, MobiSys´03), handles the dynamism of the system at the end-host session layer and combines a service-oriented abstraction with the operating system socket interface. Finally, light-weight adaptive network sockets (LANS, MC2R Jan´05), combines the lightweight operation of INS with the end-to-end semantics of SoNS, while offering richer semantics for adaptive access in shared environments. The author conclude with comments about our over-arching project aimed at formalizing a similar high-level (goal-oriented) abstraction as a language-level primitive for programming adaptive behavior