Patent ID: 6876511
Filing Date: 2005-04-05
Classification: G11B

Abstract:
1. A disk drive in which plural sets of servo data are arranged in a circumferential direction of a disk, each set containing N (a natural number satisfying N>1) types of servo data each including a unique type of servo address mark and position information, the disk drive comprising: a composite head including a write element and a read element which are offset from each other in a radial direction of the disk; means for specifying, in a self servo write process utilizing the composite head, the type of servo address mark to be detected, which is one of N types of servo address marks included in the respective N types of servo data, the specifying means operating, every time the servo data items of the same type, which are included in the respective sets of servo data, are written in the disk in a circle to switch to specification of a servo address mark unique to the type of the servo data items; means for detecting the servo address mark specified by the specifying means, in read data read from the disk by the read element of the composite head and then converted into digital data; first control means for operating every time, during the self servo process, the detecting means detects the servo address mark specified by the specifying means, to position the write element of the composite head at a target radial position on the disk on the basis of position information in servo data containing the servo address mark; second control means for operating with the write element positioned at the target radial position on the disk, to cause the write element to write a corresponding type of additional servo data item in the disk at a position offset from the position of the servo data containing the servo address mark specified by the specifying means, by a predetermined distance in the circumferential direction of the disk; and third control means for moving the composite head in the radial direction of the disk by a predetermined pitch every time sets of additional servo data items are written in the disk in a circle, each set consisting of N types of data items.