Debugging and Dynamic Modification of Embedded Systems

This paper describes the debugging and dynamic nwdijication facilities provided&nreal t ime distributed systems within the Testbed embedded systems environment. We exploit natural break-points present in a state machine programming model to pe$orm monitoring and debugging actions. This technique can avoid the probe ejJect which is a major problem in debugging concurrent and real-time systems. We describe the background debugging technique in which debugging is partially automated to jurther reduce interference. Testbed also supports a dynamic mod@cation technique that avoids m-starting the application, which may be inappropriate for embedded systems that run continuously without a notion of stopping time. Background debugging and dynamic modijication complement each other in Testbed to provide a powerful alternative to traditional debugging methods.