Abstract: A multiple redundant computer system includes three primary processor modules (PPM) and three redundant processor modules (RPM) operating synchronously. Primary and redundant processor modules are dissimilar in hardware and software for decreasing the probability of a common cause system failure. Each primary and redundant processor module receives input data from associated primary and redundant input modules respectively, executes control program and transfers output data to an output module. The output module produces a system output as the result of 2-out-of-3 voting among output data generated by PPMs. In response to PPMs hard failures, the output module still produces the system output as the result of 2-out-of-3 voting among output data generated by any combination of the PPM and the RPM. As such, the system is able to operate properly even though five-out-of six processor modules have failed.