Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Tomoo Ozaki

Makoto Takase

Kei Yasuna

Xuchu Zhu

Takao Horiguchi

Wee Hei

A system and method of writing servo write tracks to a rotating disk using a head having a read/write offset is disclosed. One embodiment utilizes a write element on the head to write the servo write tracks. A read element on the head is then positioned over the servo write tracks. The phase of a specific frequency component of the track shape error in the servo write track is measured during the positioning of the read element over the servo write track. A sine wave having a specific frequency and a phase is selected based on the measurement results. The sine wave is then applied to a servo system as a correction signal. A new servo write track is then written with the write element.

Disk drive and method of writing servo write tracks to a disk

A method for forming servo patterns on a magnetic-recording disk. The method includes moving a magnetic-recording head in an opposite direction to a pattern development direction, when there is a faulty servo pattern. The method also includes positioning a write element of the magnetic recording head on a track of the faulty servo pattern and forming a reserve servo pattern at a different circumferential location from that of the faulty servo pattern. The method includes moving the magnetic-recording head in the pattern development direction. The method further includes positioning the read element on the track of the faulty servo pattern and forming a new servo pattern in the pattern development direction at the circumferential location of the faulty servo pattern on a track disposed between the track of the faulty servo pattern and an outside diameter of the magnetic-recording disk, based on data read from the reserve servo pattern.

Method and apparatus for forming servo patterns on a magnetic-recording disk

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Kanagawa, Japan

Tomoo Ozaki