Fault-Tolerant VLIW Processor Design and Error Coverage Analysis

In this paper, a general fault-tolerant framework adopting a more rigid fault model for VLIW data paths is proposed. The basic idea used to protect the data paths is that the execution result of each instruction is checked immediately and if errors are discovered, the instruction retry is performed at once to overcome the faults. An experimental architecture is developed and implemented in VHDL to analyze the impacts of our technique on hardware overhead and performance degradation. We also develop a comprehensive fault tolerance verification platform to facilitate the assessment of error coverage for the proposed mechanism. A paramount finding observed from the experiments is that our system is still extremely robust even in a very serious fault scenario. As a result, the proposed fault-tolerant VLIW core is quite suitable for the highly dependable real-time embedded applications.