| 摘要 |
PURPOSE:To shorten an access time for a file system that is often modified by providing a means to record an identification mark to identify the validity/ invalidity of a data stored in an information recording area, and executing the identification of a valid data. CONSTITUTION:In a direct-read-after-write type information recorder to record sequential information in an information recording medium, the means to record an identification mark to identify the validity/invalidity of a data recorded in an information storage area corresponding to the information recording area of the information recording medium is provided. Accordingly, the identification mark is such that one bit corresponds to a piece of data set including the object of processing and a processing, and a valid piece of it is represented by '1'. After the data is written for a determined number of sectors, one sector is read, whether it is a valid data or not is checked, if it is a valid data, an identification mark is made in '1' for it, but if it is invalid, the mark is made in '0'. After thus checking the data for the determined number of sectors, the identification marks are written. As a result, at the time of reading, selective readings in accordance with the validity/invalidity of the data can be executed, and the file access speed can be made maximal.
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