Dynamic Software Update of Resource-Constrained Distributed Embedded Systems

Changing demands, software evolution, and bug fixes require the possibility to update applications as well as system software of embedded devices. Systems that perform updates of resource-constrained nodes are available, but most approaches require a complete restart of the node after installing or updating software. Restarting the node results in the loss of important system state, such as routing information or sensor calibration values. Rebuilding this information requires time and energy. In this paper we present an online state-preserving update system for resourceconstrained nodes. A remote incremental linking approach is used to generate node-specific and execution-state dependent code. Compiler-generated symbol, relocation, and debugging information is used to determine whether a dynamic update of the running system is possible and how it can be achieved.