| 摘要 |
PURPOSE:To localize a faulty point during the course of a directory file updating process, by constituting the directory file double and dividing the file into a data section for storing defining information and index section for managing defining information, and then, serializing the updating process. CONSTITUTION:When a directory implementing request arrives, an access controlling section writes a directory body section and, when the writing is normally completed, edits updating information and actuates a restoration controlling section. The restoration controlling section writes the updating information in a journal file. When the writing in the journal file is normally completed, an index section is updated and a directory file is written. If an interruption of process is produced due to a power failure, improper program, etc., in the course of the writing in the directory body, the index section is not updated and, as a result, the writing controlling state can be secured. Moreover, when an interruption takes place while the index section is written, the index section is updated in accordance with the journal and the index section can be restored.
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