| 摘要 |
PURPOSE:To improve an using efficiency of a magnetic disk by erasing unnecessary head positioning information group of the magnetic disk by an electric conduction. CONSTITUTION:A magnetic recording medium 16 rotates and moves in a direction shown by an arrow A. A magnetic head 2 is disposed at an outer peripheral and an inner peripheral positions from a track 17. When the head 2 is situated at a position capable of erasing an unnecessary head positioning information group, to the head, a high level erasing instruction signal 10 is impressed to erase mainly an outer most peripheral side of the information group. Then, a magnetic head 3 is moved and disposed inward from the position of the head 2, and erases a part of the information group 1. Next to the head 3, in a sequence of a magnetic head 4, a head 5, a head 6, a head 7, a head 8 and a head 9, the magnetic head is successively moved, carries out the erasing operation one by one and erases all the unnecessary head positioning information group 1. Thereby an using efficiency of a magnetic disk is improved.
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