Online marking of defective cells by random flies

Defect-tolerance, the ability to overcome unreliability of components in a system, will be essential to realize computers built by nanotechnology. This paper presents a novel approach to defect-tolerance for nanocomputers that are based on self-timed cellular automata, a type of asynchronous cellular automaton. According to this approach, defective cells are detected and isolated by configurations of random flies that move around in cellular space. We show that detection and isolation are realized in an on-line manner, i.e., while computation takes place.