Optimizing Relocatable Code for Efficient Software Update in Networked Embedded Systems

摘要

Recent advances in Microelectronic Mechanical Systems (MEMS) and wireless communication technologies have fostered the rapid development of networked embedded systems like wireless sensor networks. System software for these self-organizing systems often needs to be updated for a variety of reasons. We present a holistic software update (i.e., reprogramming) system called R3 for networked embedded systems. R3 has two salient features. First, the binary differencing algorithm within R3 (R3diff) ensures an optimal result in terms of the delta size under a configurable cost measure. Second, the similarity preserving method within R3 (R3sim) optimizes the binary code format for achieving a large similarity with a small metadata overhead. Overall, R3 achieves the smallest delta size compared with other software update approaches such as Stream, Rsync, RMTD, Zephyr, Hermes, and R2 (e.g., 50%-99% reduction compared to Stream and about 20%-40% reduction compared to R2). R3's implementation on TelosB/TinyOS is lightweight and efficient.