gence of Networking Abstractions and Techniques in TinyOS Philip Levis , Sam Madden , David Gay , Joseph Polastre , Robert Szewczyk , Alec Woo , Eric Brewer and David Culler EECS Department Intel Research Berkeley CSAIL University of California, Berkeley 2150 Shattuck Avenue MIT Berkeley, California 94720 Berkeley, California 94704 Cambridge, MA 02139 The constraints of sensor networks, an emerging area of network research, require new approaches in system design. We study the evolution of abstractions and techniques in TinyOS, a popular sensor network operating system. Examining CVS repositories of several research institutions that use TinyOS, we trace three areas of development: single-hop networking, multi-hop networking, and network services. We note common techniques conclusions on the emerging abstractions as well as the novel constraints that have shaped them.