Multiple computer system.

摘要

In a multiple computer system in which a plurality of computer stations are connected for mutual data transfer via a common data bus, at least one computer station is provided with a fail safe facility which prevents disruption of the entire system due to malfunction of the computer station. The computer is preprogrammed to perform an input/output circuit diagnosis routine after power-up and before control program execution which causes the input/output circuit to output a coded pulse train signal. An abnormality detection circuit receives the coded pulse signal, converts it to a parallel-bit word, and compares the derived word to a stored, predetermined word. If the words match, the detection circuit causes a switching circuit to connect the computer to the common data bus; otherwise, the computer remains disconnected from the rest of the multiple computer system.