| 摘要 |
A disk control unit and method thereof enable read-in speed to be improved regarding a file which is stored in a fixed drive discontinuously. A prefetch decision circuit receives instructions from an instruction decode circuit. The prefetch decision circuit decides to which partition the instructions belong while comparing them with information of a partition map. The prefetch decision circuit presumes to which file the instructions belong while comparing them with information of a predictive cache entry. Next, the prefetch decision circuit directs read-in of a part of the file to the disk control circuit while determining to which block the instructions are connected to which block, thus storing prefetch data being read-in in disk cache. An instruction decode circuit, when read-in instruction is sent from a computer, compares the data regarding the instruction with the prefetch data. When the data regarding the instructions coincides with the prefetch data, the instruction decode circuit transmits the prefetch data of the disk cache to the computer without performing read-in operation on the fixed drive practically. Thereby, the unit causes the read-in speed to be improved in connection with the file which is stored discontinuously in the fixed drive.
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