| 摘要 |
PURPOSE:To reduce the number of stand-by input-output controlling sections to be set, by providing stand-by controlling sections to every group of input- output controlling sections whose number is less than the total number of input- output controlling sections or which have the identity and switching them at the time of trouble. CONSTITUTION:Since a change-over controlling section 24 outputs the 1st switching signal 25 if an input-output controlling section 5 becomes defective due to a fault, etc., when the central processing section 4 of the currently used system A is normal, a switching means 23 switches the input-output controlling section from the defective section 5 to a stand-by input-output controlling section 21 and connects an external device 1 with the stand-by section 21. Even if another input-output controlling section 6 or 7 becomes defective, the same switching operations is performed by the switching means 23. When the central processing section 4 of the currently used system A is in trouble, the change-over controlling means 24 outputs the 2nd switching signal 26 to a bus switching section 22. Therefore, the bus switching section 22 sets another central processing section 13 to its actuated condition. |
