A proposed fault-tolerant microcomputer system

Past experience with fault-tolerant and other reliability techniques has focused on such specialized systems as spacecraft control computers and telephone switches. However, current technology trends strongly suggest that specific reliability techniques should be developed and implemented for a large number of low-cost systems such as microprocessor-based controllers, instruments, and other industrial devices. In this paper a fault-tolerant microcomputer architecture which is particularly designed for industrial control and manufacturing is proposed. For this system, voting has been considered as a very appropriate fault-tolerant technique. However, voting at the component level and at the bus-level have been ruled out due to the unreliability of the voters required and their high cost. System voting without an explicit voter is finally selected. Analysis shows that the system has a higher reliability than either a nonredundant system or a bus-level voting system. Its mission time has been increased by a factor of 2.5 over non-redundant systems.