Issue No. 07 - July (1968 vol. 17)
H. Mine , Dept. of Applied Mathematics and Physics Faculty of Engineering Kyoto University
In Theorem 3, it is clearly stated that the fail-safe output of a basic function is severely restricted by the failed output of the preceding basic functions (though two Iff's in the statement of Theorem 3 should be If's). It is obvious, as a matter of course, that a single failure of an element in a logical circuit may cause different effects on its following logical functions. It should be noted here that we do not deal with types of internal failures of logical circuits but with outputs of logical functions being restricted by their following logical functions. If open inputs to the terminal logic shown in Fig. 1 of Mr. Foster's comment are allowed, then the conditions in Theorem 3 are not satisfied any more. This apparently does not cause any inconsistency in our paper.<sup>1</sup>Examples of fail-safe NOR circuits shown in Section V are illustrated for the construction of fail-safe logical systems only with NOR circuits. This should have been noted in our paper.
H. Mine and Y. Koga, "Authors' Reply<sup>3</sup>," in IEEE Transactions on Computers, vol. 17, no. , pp. 702, 1968.