| 摘要 |
PROBLEM TO BE SOLVED: To prevent an error and to unnecessitate counter measure such as retry by providing a servo pulse generation means for generating a servo pulse is accordance with the detection of the servo area of another surface when the servo area of an objective surface isn't detected. SOLUTION: A data pulse extracted by a read/write IC 19 is sent to a servo processing circuit 20. The circuit 20 detects a servo sector pattern included in the servo area from the data pulse. If the servo sector pattern is detected and there is no decoding error of servo information, the circuit 20 generates the servo pulse corresponding to the next servo pulse at every time when the servo area is detected normally. On the contrary, when there is error, the circuit 20 informs a CPU of the error. When the CPU 21 receives error information, the CPU 21 switches a using head from a head 12b of an objective disk surface 11b side to a head 12a on a disk surface 11a inverse to the surface 11b. |
