Always on, always connected mobile computing

We discuss an always on, always connected (AOAC) usage model for notebook PCs, and how it is enabled by the availability of ubiquitously deployed wireless data infrastructures. An experimental wide area information filtering and delivery system was used to identify missing technologies required by AOAC PCs. We present three findings: the critical role of narrowband data messaging (such as paging) in making data pushing applications financially viable; modifications to the Windows/sup */ communications infrastructure to integrate wireless data pipes with existing PC APIs; and a new transport protocol which adds advanced data capabilities to narowband wireless messaging networks, as well as providing a familiar sockets interface that hides applications from the differences in networks (e.g. 2 way paging and GSMs SMS appear the same to the application). Some other interesting aspects of the experimental system are also described, including the use of cell level location information for information filtering.