| 摘要 |
PURPOSE:To recover a file nearly to an original file even when managing information in the file is destroyed by executing judgement for the correctness of data in a managing information storage area at the time of starting up a system operation, and duplicating the data in the managing information storage area when the data is correct, and the data in a backup area when it is incorrect. CONSTITUTION:The backup area B is set in the memory area A of the managing information, and the trial read of the data in the memory area A of the managing information is performed first when the system operation is started up such as the application of a power source, etc., and when normal data is obtained, the data is duplicated on the backup area B, and when no normal data is obtained, the data in the backup area B is duplicated on the managing area A. Therefore, only correct managing information is always stored sequentially in the backup area B, and even when the managing information in the managing information area A is destroyed, recovery to the managing information just before destruction can be performed automatically. In such a way, it is possible to prevent the whole of the file from being impossible to be read and written, thereby, file protection can be performed sufficiently. |
