Hot-Swapping architecture extension for mitigation of permanent functional unit faults

Due to latest advances in semiconductor integration, systems are becoming more susceptible to faults leading to temporary or permanent failures. We propose a new architecture extension suitable for arrays of functional units, that will provide testing and replacement of faulty units, without interrupting normal system operation. The extension relies on data path switching controlled by a hot-swapping algorithm, by use of which functional units are tested and replaced by spares if necessary, ensuring permanent operation while the spares last. The Hot-Swapping functionality could be added as a case study on a sample architecture, with an overhead of 74-87%. Also, a prototype chip (4.2 mm times 2.1 mm) targeted to operate at 166 MHz has been fabricated, using 65 nm process technology.