| US 7,532,424 B2 | ||
| Method of writing pattern on media and data storage device | ||
| Fuminori Sai, Kanagawa (Japan); Kohji Takasaki, Kanagawa (Japan); Masahiro Shohda, Kanagawa (Japan); and Hiroshi Yanagisawa, Kanagawa (Japan) | ||
| Assigned to Hitachi Global Storage Technologies Netherlands B.V., Amsterdam (Netherlands) | ||
| Filed on Jul. 26, 2006, as Appl. No. 11/494,684. | ||
| Claims priority of application No. 2005-223332 (JP), filed on Aug. 01, 2005. | ||
| Prior Publication US 2007/0025007 A1, Feb. 01, 2007 | ||
| Int. Cl. G11B 20/10 (2006.01); G11B 21/02 (2006.01) | ||
| U.S. Cl. 360—51 [360/75] | 20 Claims |
| 1. A method for reading a pattern by a read device associated with writing a new pattern by a write device provided at a different
radial location than a read device in a rotating media, the method comprising:
writing plural reference patterns on plural sectors of a first track of the rotating media;
determining a read time value of each reference pattern by measuring a read time between reference patterns for each of the
plural reference patterns plural times;
determining a target time value based on the determined read time value;
changing a clock frequency based on a difference between the read time value of each of the respective reference patterns
and the determined target time value simultaneously with reading out the plural reference patterns; and
writing a new pattern on a second track with the changed clock frequency after a delay time obtained for each sector has passed
from the read time of the respective reference patterns.
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