On the practicality of using intrinsic reconfiguration for fault recovery

Evolvable hardware (EHW) combines the powerful search capability of evolutionary algorithms with the flexibility of reprogrammable devices, thereby providing a natural framework for reconfiguration. This framework has generated an interest in using EHW for fault-tolerant systems because reconfiguration can effectively deal with hardware faults whenever it is impossible to provide spares. But systems cannot tolerate faults indefinitely, which means reconfiguration does have a deadline. The focus of previous EHW research relating to fault-tolerance has been primarily restricted to restoring functionality, with no real consideration of time constraints. In this paper, we are concerned with EHW performing reconfiguration under deadline constraints. In particular, we investigate reconfigurable hardware that undergoes intrinsic evolution. We show that fault recovery done by intrinsic reconfiguration has some restrictions, which designers cannot ignore.