Issue No. 02 - February (1973 vol. 22)
S.L. Hight , Bell Telephone Laboratories, Inc.
The reliability of digital computing systems is a significant problem. A scheme using multiply redundant computing devices with a majority voting device to determine the output has been shown to improve the reliability of that output. In this paper, a devices called a dissent detector is suggested as an addition to the system. The function of this device is that of an alarm to indicate the quality of the information (likelihood that the information is correct). Dissent is defined as a family of logic functions that compare the outputs of the voters to the output of the majority gate and report the disagreement or degree of disagreement that takes place. The operation of a dissent-detector that reports any disagreement in a triplicated majority voting system is demonstrated by example. The example illustrates the importance of the dissent information to the conditional reliability of the output of the majority gate. The results show that, with very little additional equipment, the conditional reliability of a majority voting system can be greatly enhanced. In fact, the conditional reliability of the example system exceeds the reliability of any of the system components, including the majority gate and the dissent detector.
Dissent, majority voting system, redundancy, reliability.
S. Hight and D. Petersen, "Dissent in a Majority Voting System," in IEEE Transactions on Computers, vol. 22, no. , pp. 168-171, 1973.