Adaptive fault tolerant systems: reflective design and validation

Reflection has been used with some success, since quite a few years now, for dealing with separation of concerns and transparency of fault-tolerance mechanisms for the application. Nevertheless, it has also shown some concern regarding the control of fine-grain information such as thread control or other deep aspects of the platform. We propose here the use of a new concept, called multi-level reflection, for firstly solving these issues, but also for introducing more adaptation into fault-tolerant reflective architectures. We also discuss some essential validation issues of reflective systems, which are still a challenge for future research.