| 摘要 |
PURPOSE:To contrive a quick search by making the distance of jumping movement larger than before and repeating track jumping movement when a target address is not obtained within a specified time from generation of an address search command. CONSTITUTION:A processor compares present address information with target address information from address information extracted in a data extracting circuit 11, and calculates the number of tracks existing between the two addresses. The number of tracks N obtained by the calculation is set as the number of tracks N' to be counted, and then, a pickup 1 is moved by jumping in the direction of target address. At the same time, the processor judges whether number of count arrives at N' or not, and when not, discriminates from the output data of a timer whether m-second is lapsed from the generation of an address search command, and enlarges the distance of movement and repeats track jumping operation only when m-second not yet is lapsed.
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