The Use of Triple-Modular Redundancy to Improve Computer Reliability

One of the proposed techniques for meeting the severe reliability requirements inherent in certain future computer applications is described. This technique involves the use of triple-modular redundancy, which is essentially the use of the two-out-of-three voting concept at a low level. Effects of imperfect voting circuitry and of various interconnections of logical elements are assessed. A hypothetical triple-modular redundant computer is subjected to a Monte Carlo program on the IBM 704, which simulates component failures. Reliability is thereby determined and compared with reliability obtained by analytical calculations based on simplifying assumptions.