This SGER award supports a study that will contribute to a new Cyber-Physical Systems (CPS) vision being developed in NSF's Computer and Network Systems division. The goal of CPS research is new science and engineering methodologies that integrate the interacting cyber and physical elements of future engineered systems. CPS seeks new design principles and systems technology that can routinely yield high-confidence physical and engineered systems. This study explores a central aspect of CPS: the extent to which the mismatch between the core abstractions of computation and properties of physical processes impedes progress. In the physical world, the passage of time is inexorable and concurrency is intrinsic. Neither of these properties is present in today's computing and networking abstractions. The study will consider these and other central issues in the foundations of CPS.