| 摘要 |
PURPOSE:To increase the using efficiency of a recording surface, by rexording both the data and servo signal on the same surface of a double-layer coated magnetic disk and then reading them by the same head. CONSTITUTION:A magnetic layer 12 and a magnetic layer 13 having much higher resistance to magnetism are coated in a sandwich form on both surfaces of a base 11 for a magnetic disk 8. The data is written and read into and out of the layer 13 by means of a core 15 of a head 9 or 10. The magnetic field generated from the core 15 is not so high as to invert the magnetization of the layer 12. A servo track writes the data into the layers 12 and 13 in the process of production of the disk 8 and then erases the servo signal of the layer 13 by the magnetic field generated from a core 14. If the servo signal is set at a frequency lower enough than the frequency of the data, it is easily separated through a filter circuit. |
