Extending the verification capabilities of middleware for reliable distributed self-adaptive systems

The design of the embedded software for industrial systems progressively integrates more intelligent functions to ease the integration between the factory floor hardware and operator-friendly control front ends. New software development paradigms such as service oriented architecture (SOA) make it possible by embedding small footprint web servers inside small embedded devices that are connected to the actuators which they control. In general, the timing requirements of such distributed systems are not in the front plane and temporal guarantees provided by most solutions are typically best effort. iLAND is an example of a middleware that supports communication and reconfiguration of distributed services, ensuring temporal correctness. It includes the logic for adapting the architectural structure of a service-based application (i.e., number and connections of the software pieces/functions) to respond to operator requests in a time-deterministic way, focusing only on the temporal correctness. In this paper, we apply the principles of autonomic computing to the middleware design, and we provide a high-level description on how its verification process could be extended beyond the purely temporal properties using more comprehensive formal techniques. We exemplify these ideas with a modified on-line verification manager that suits the needs of a kind of systems with specific timing and functional constraints.