Fault Tolerant Memory Design for HW/SW Co-Reliability in Massively Parallel Computing Systems

A highly dependable embedded fault-tolerant memory architecture for high performance massively parallel computing applications and its dependability assurance techniques are proposed and discussed in this paper. The proposed fault tolerant memory provides two distinctive repair mechanisms: the permanent laser redundancy reconfiguration during the wafer probe stage in the factory to enhance its manufacturing yield and the dynamic BIST/BISD/BISR (built-in-self-test-diagnosisrepair)-based reconfiguration of the redundant resources in field to maintain high field reliability. The system reliability which is mainly determined by hardware configuration demanded by software and field reconfiguration/repair utilizing unused processor and memory modules is referred to as HW/SW Co-reliability. Various system configuration options in terms of parallel processing unit size and processor/memory intensity are also introduced and their HW/SW Co-reliability characteristics are discussed. A modeling and assurance technique for HW/SW Co-reliability with emphasis on the dependability assurance techniques based on combinatorial modeling suitable for the proposed memory design is developed and validated by extensive parametric simulations. Thereby, design and implementation of memory-reliability-optimized and highly reliable fault-tolerant field reconfigurable massively parallel computing systems can be achieved.