Patent ID: 8862934

Claim:
A redundant computing system wherein: an input of a first arithmetic processing unit having a first storage unit and an input of a second arithmetic processing unit with the same function as that of the first arithmetic processing unit and having a second storage unit are connected to an input control unit; an output of the first arithmetic processing unit and an output of the second arithmetic processing unit are connected to a comparator and an output control unit; the redundant computing system includes a diagnosis control unit that diagnoses the first arithmetic processing unit and the second arithmetic processing unit; and the first arithmetic processing unit and the second arithmetic processing unit perform the same processing in synchronization with each other, and wherein: the diagnosis control unit has a function to control such that, in the course of the synchronous performance of the same processing between the first arithmetic processing unit and the second arithmetic processing unit, the second arithmetic processing unit is diagnosed while the first arithmetic processing unit continues the processing, and after completion of the diagnosis, a value in the first storage unit is copied to the second storage unit, and then the first arithmetic processing unit and the second arithmetic processing unit are caused to resume the synchronous performance of the same processing; the diagnosis control unit has a function to control such that, in the course of the synchronous performance of the same processing between the first arithmetic processing unit and the second arithmetic processing unit, the first arithmetic processing unit is diagnosed while the second arithmetic processing unit continues the processing, and after completion of the diagnosis, a value in the second storage unit is copied to the first storage unit, and then the first arithmetic processing unit and the second arithmetic processing unit are caused to resume the synchronous performance of the same processing; the input control unit has a function to control the input of the redundant computing system according to a state of the diagnosis performed by the diagnosis control unit; and the output control unit has a function to control the output of the redundant computing system based on a comparison result by the comparator and a diagnosis result by the diagnosis control unit, the redundant computing system further comprising: a first voltage/frequency control unit for controlling at least one of voltage and frequency of the first arithmetic processing unit; and a second voltage/frequency control unit for controlling at least one of voltage and frequency of the second arithmetic processing unit.