Fault-Tolerant Systems with Concurrent Error-Locating Capability

Fault-tolerant systems have found wide applications inmilitary, industrial and commercial areas. Most of these systems areconstructed by multiple-modular redundancy or error control codingtechniques. They need some fault-tolerant specific components (such asvoter, switcher, encoder, or decoder) to implement error-detecting orerror-correcting functions. However, the problem of error detection,location or correction for fault-tolerance specific componentsthemselves has not been solved properly so far. Thus, the dependabilityof a whole fault-tolerant system will be greatly affected. This paperpresents a theory of robust fault-masking digital circuits forcharacterizing fault-tolerant systems with the ability of concurrenterror location and a new scheme of dual-modular redundant systems withpartially robust fault-masking property. A basic robust fault-maskingcircuit is composed of a basic functional circuit and an error-locatingcorrector. Such a circuit not only has the ability of concurrent errorcorrection, but also has the ability of concurrent error location.According to this circuit model, for a partially robust fault-maskingdual-modular redundant system, two redundant modules based onalternating-complementary logic consist of the basic functionalcircuit. An error-correction specific circuit named asalternating-complementary corrector is used as the error-locatingcorrector. The performance (such as hardware complexity, time delay) ofthe scheme is analyzed.