| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic disk medium which has a small diameter size usable for a portable computer apparatus and video recorder as well and achieves a recording capacity above several hundreds MB, and to provide a recording and reproducing method therefo. SOLUTION: The magnetic disk medium is provided with a substantially nonmagnetic layer and a magnetic layer formed by dispersing a hexagonal ferrite powder into a binder in this order on a support, in which the external diameter of the magnetic disk medium is≥20 to≤50 mm, the quantity of wobbling of the surface in a perpendicular direction in the outer peripheral part of the disk in recording and reproducing is≤50μm, and the quantity of wobbling of the surface in a perpendicular direction in the inner peripheral part is≤25μm. The recording and reproducing method comprises performing recording and reproducing at such a rotating speed at which the quantity of wobbling of the surface in the perpendicular direction in the outer peripheral part of the disk attains≤50μm and that the quantity of wobbling of the surface in the perpendicular direction in the inner peripheral part attains≤25μm. COPYRIGHT: (C)2004,JPO
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