Concurrent self-checking for microprogrammed control units: an analytical survey

A comparative survey and systematic categorisation of the main western and soviet publications over the past five years in the area of concurrent techniques for control-flow checking for microprocessor-based systems is presented. The types of faults encountered in microprogram execution are described, and a number of techniques for detecting these faults are outlined. These include methods for partitioning the control flow-graph to allow checking, and methods for forming and transforming vertex check keys. A number of algorithms are presented, together with examples of architectures for self-checking microprogrammed control units, and a discussion of their engineering implementation.