摘要 |
PROBLEM TO BE SOLVED: To quicken an access to a positionally discontinuous data arranged on a recorder. SOLUTION: A retrieval system comprises a controller for controlling retrieval processing, and the recorder mounted with a read-ahead command for storing an assignment data in a cache memory built in the recorder. The controller indicates data read-ahead required in the next to the recorder, using the read-ahead command, during processing of the data, the recorder reads out the assigned data from a recording medium, to be stored into the cache memory, and the data is thereby read quickly from the recorder built in the recorder, without accessing the recording medium, when the controller reads the next data from the recorder. A hit rate of the cache memory is also enhanced to quicken the reading, by adding a priority and a protection flag to an area indicated and read by the read-ahead command to control efficiently the cache memory. COPYRIGHT: (C)2008,JPO&INPIT
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