| 摘要 |
PURPOSE:To prevent a load from being one-sided and to perform copying operation to the end even if trouble occurs to one control part by providing plural control parts and copying data from an in-use system storage part to a stand-by system storage part on a time-division basis when the stand-by system storage part is incorporated while only the in-use system storage part is used. CONSTITUTION:When a control part 100 sends a copying indication to the in-use system storage part 30 and stand-by system storage part 400, the in-use system storage part 300 sends only certain blocks from an address indicated in a copy address storage part 310 to the stand-by system storage part 400, an address after the transferred blocks is stored in a memory address storage part 310, and the stand-by storage part 400 stores sent data in sequence. Then when a control part 200 detects an in-copying signal which is sent from the in-use system storage part 300, copying operation is indicated and the data stored in the in-use storage part 300 are stored in the in-use system storage part 400. Then both the control parts 100 and 200 sends the indication of copying operation to the in-use system storage part 300 until the in-copying signal sent from the in-use system storage part 300 is cleared.
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