| 摘要 |
PURPOSE: To prevent the break of signals and to facilitate the exchange of software and hardware with no interruption of service by restoring the data which are managed by a CPU consisting of a main unit containing a CPU, a main storage part and a nonvolatile storage part and an I/O unit containing an I/O storage part based on the state of every unit. CONSTITUTION: A CPU 1 expands the data stored in a nonvolatile storage part 3 to the work area or a storage part 2 when the part 3 and its data are normal and then expands the default data to the work area of the part 2 if the part 3 and its data are not normal. At the same time, the CPU 1 expands the data stored in the I/O storage parts 5 to 8 to the work area when the parts 5 to 8 and their data are normal and performs nothing if the parts 5 to 8 and their data are not normal to finally restore the data on the work area at the part 3 regardless of the normal or abnormal states of the parts 5 to 8. |
