1. Field of the Invention
The present invention relates to a data recording disk, a disk drive device and a method for writing servo patterns on a data recording surface of a rotating data recording disk, and more particularly to a method, data recording disk and disk drive having servo patterns that improve efficiency of head positioning and data storage.
2. Description of Related Art
A giant magneto resistive (GMR) head has been developed as a next generation read/write head of a hard disk drive device. The GMR head can generate an output signal which is larger than an output signal generated by a prior magneto resistive (MR) head. The capability of generating the large output signal causes a reduction of a head width of the GMR head.
The GMR head is fabricated by the fabrication process of the MR head, and hence a head width of the GMR head is determined by a tolerance of the fabrication process of the MR head. It is assumed that the head width of the prior MR head is 2 xcexcm, (1 xcexcm=10xe2x88x926 m), the head width of the GMR head is 1 xcexcm, and the tolerance of the fabrication technology of the MR head is 0.4 xcexcm. Since the tolerance of the 0.4 xcexcm is applied to both the MR head and GMR head, the head width of the MR head is 2 xcexcmxc2x10.4 xcexcm, that is, the track width of the MR head varies from 1.6 xcexcm to 2.4 xcexcm, and a variance of the head width is 20%. The head width of the GMR head is 1 xcexcmxc2x10.4 xcexcm, that is, the head width of the GMR head varies from 0.6 xcexcm to 1.4 xcexcm, and a variance of the head width is 40%. In this manner, the variance of the head width of the MR head is 20%, while the variance of the head width of the GMR head is 40% which is larger than that of the MR head.
An uniform track pitch is used in the track arrangement of the prior MR technology. A track pitch is a distance between a track center of one track and a track center of the next track.
If the uniform track pitch of the MR head is used for the GMR head, the following first problem, as shown in FIG. 1 occurs. As described above, the head width of the GMR head varies from 0.6 xcexcm to 1.4 xcexcm. For simplifying the description, three kinds of the GMR heads 1, 2 and 3 are shown in FIG. 1, i.e., the GMR head 1 has the 1.4 xcexcm head width, the GMR head 2 has the 1.0 xcexcm head width, and the GMR head 3 has the 0.6 xcexcm head width. The track width of all the tracks 1, 2 and 3 are the same width, i.e., 1.4 xcexcm, which is the largest width of the GMR head, and the uniform track pitch is used for all the tracks. A gap is provided for separating the adjacent two tracks. And, the center of the GMR heads 1, 2 and 3 are aligned to the track center of each track, respectively. It is apparent that useless or wasted space exists between the GMR heads 1 and 2, and between the GMR heads 2 and 3.
The following second problem occurs with respect to the servo patterns provided in the track. The servo patterns A and B are written to define the tracks, and read by the head to generate a feedback signal which is supplied to a hard disk control device. The detail of the servo patterns A and B are shown in FIG. 4(B) and (C). The servo pattern A has alternately arranged opposite magnetization direction, and the servo pattern B has an uniform magnetization direction. The hard disk control device responds to the feedback signal to position the center of the head on the track center. It is assumed that the GMR heads 1, 2 and 3 are shifted from the track center by a distance of 10% of the track pitch, as shown by the dashed line in FIG. 1. For example, it is assumed that the track pitch=track widthxc3x971.1=1.4 xcexcm=1.1xc3x971.6 xcexcm, and the shift distance=track pitchxc3x970.1=0.16 xcexcm. In this case, the GMR heads 1, 2 and 3 are shifted with respect to the servo pattern B, and the variation of the levels of the feedback signals sensed by the GMR heads 1, 2 and 3 are as follows.
In the case of the GMR head 1 of the 1.4 xcexcm head width: 0.16 xcexcm/1.41 xcexcm=0.114. That is, the level of feedback signal is reduced by 11.4%. In the case of the GMR head 2 of the 1.01 xcexcm head width: 0.16 xcexcm/1.0 xcexcm=0.16. That is, the level of feedback signal is reduced by 16%. In the case of the GMR head 3 of the 0.6 xcexcm head width: 0.16 xcexcm/0.6 xcexcm=0.267. That is, the level of feedback signal is reduced by 26.7%.
The variation of the levels of the feedback signal sensed by the prior MR head of 2.4 xcexcm head width, the prior MR head of 2.0 xcexcm head width, and the prior MR head of 1.6 xcexcm head width are, as follows. It is assumed that the track pitch=track widthxc3x971.1=2.4 xcexcmxc3x971.1=2.6 xcexcm, and the shift distance=track pitchxc3x970.1=0.26 xcexcm.
In the case of the MR head of the 2.4 xcexcm head width: 0.26 xcexc m/2.4 xcexc m=0.108. That is, the level of the feedback signal is reduced by 10.8%. In the case of the MR head of the 2.0 xcexcm head width: 0.26 xcexcm /2.0 xcexcm=0.13. That is, the level of the feedback signal is reduced by 13%. In the case of the MR head of the 1.6 xcexcm head width: 0.26 xcexcm/1.6 xcexcm=0.163. That is, the level of the feedback signal is reduced by 16.3%.
In this manner, when the head is shifted by the distance of track pitch multiplied by A, the level of the feedback signal of the MR head to the hard disk control device varies from 10.8% to 16.3%, while the level of the feedback signal of the GMR head to the hard disk control device varies from 11.4% to 26.7%.
The range of the variation of the feedback signals to the hard disk control device should be small, since if the range of the variation becomes large, undesirable phenomenon, such as an oscillation of the entire servo system may occur.
It can be seen then that there is a need for a method, data recording disk and disk drive that eliminates useless or wasted space on a data recording disk.
It can also be seen that there is a need for a method, data recording disk and disk drive that provides a track pitch that varies depending o the track width.
It can also be seen that there is a need for a method, data recording disk and disk drive that provides a uniform level of variation I the feedback signals.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a data recording disk that includes a first data recording surface and a second data recording surface, wherein a track pitch of adjacent data recording tracks of the first data recording surface differs from a track pitch of adjacent data recording tracks of the second data recording surface.
A data recording disk according to the present invention includes a first data recording surface and a second data recording surface, wherein the number of data recording tracks of the first data recording surface differs from the number of data recording tracks of the second data recording surface, and the a gap width between the data recording tracks of the first data recording surface differs from a gap width between the data recording tracks of the second data recording surface.
A data recording disk according to the present invention includes a first data recording surface and a second data recording surface, wherein the number of data recording tracks of the first data recording surface differs from the number of data recording tracks of the second data recording surface.
A disk drive device according to the present invention includes data recording surfaces on a rotating data recording disk, each of the data recording surfaces is provided with a read/write head, wherein the number of data recording tracks of a first data recording surface differs from the number of data recording tracks of a second data recording surface, and a gap width between the data recording tracks of the first data recording surface differs from a gap width between the data recording tracks of the second data recording surface.
All data recording tracks of the first data recording surface have substantially the same track width, and all gaps of the first data recording surface have substantially the same gap width.
All data recording tracks of the second data recording surface have substantially the same track width, and all gaps of the second data recording surface have substantially the same gap width.
Data is written in a direction from an outer most data recording track to an inner most data recording track of the first data recording surface, then the data is written in a direction from an outer most data recording track to an inner most data recording track of the second data recording surface.
Addresses of data recording tracks are successively assigned from an outer most data recording track to an inner most data recording track of the first data recording surface, and the address of the inner most data recording track of the first data recording surface is followed by an address of an outer most data recording track of the second data recording surface, and the addresses on the second data recording surface are successively assigned from the outer most data recording track to an inner most data recording track of the second data recording surface.
A method according to the present invention for writing servo patterns for defining a plurality of data recording tracks on a rotating data recording disk by a read/write head contained in a disk drive device, includes positioning the read/write head at one position along a radial direction of the rotating data recording disk, writing servo patterns on the rotating data recording disk by the read/write head positioned at the one position, reading the servo patterns by the read/write head positioned at the one position to detect an amplitude of output signal generated by the read/write head, moving the read/write head from the one position along the radial direction, reading the servo patterns by the read/write head moved from the one position to detect that an amplitude of output signal generated by the moved read/write head becomes 50xe2x88x92Gw/2% of the amplitude of output signal generated by the read/write head when it is positioned at the one position, wherein the Gw is a predetermined gap width between the data recording tracks, stopping the read/write head when the detection is made, and overlappingly writing the servo patterns on the rotating data recording disk by the stopped read/write head.
A method according to the present invention for writing servo patterns for defining a plurality of data recording tracks on a rotating data recording disk by a read/write head contained in a disk drive device, includes specifying a gap width between adjacent data recording tracks, writing servo patterns for defining a plurality of data recording tracks separated by the specified gap width on the rotating data recording disk by the read/write head, detecting that the total number of data recording tracks is smaller than a predetermined number, specifying an overlap width of adjacent data recording tracks, and rewriting servo patterns for defining a plurality of data recording tracks overlapped each other by the overlap width on the rotating data recording disk by the read/write head, the rewriting of servo patterns including positioning the read/write head at one position along a radial direction of the rotating data recording disk, rewriting the servo patterns on the rotating data recording disk by the read/write head positioned at the one position, reading the rewritten servo patterns by the read/write head positioned at the one position to detect an amplitude of output signal generated by the read/write head, moving the read/write head from the one position along the radial direction, reading the rewritten servo patterns by the read/write head moved from the one position to detect that an amplitude of output signal generated by the moved read/write head becomes 50+Y/2% of the amplitude of output signal generated by the read/write head when it is positioned at the one position, wherein the Y is the overlap width, stopping the movement of the read/write head when the detection is made, and rewriting the servo patterns on the rotating data recording disk by the stopped read/write head stopped.
A method according to the present invention for writing servo patterns for defining a plurality of data recording tracks on each of a plurality of data recording surfaces on rotating data recording disks by a read/write head provided on each of the plurality of data recording surfaces contained is a disk drive device, includes specifying a gap width between adjacent data recording tracks, writing servo patterns on a plurality of servo tracks for defining the plurality of data recording tracks separated by the specified gap width on one data recording surface by its read/write head, storing a count value indicating the number of servo tracks written on the one data recording surface, repeating the writing of servo patterns and storing the count value until the servo patterns are written on all data recording surfaces, determining whether the total number of data recording tracks written on the data recording surfaces exceeds a predetermined number, or not, specifying an overlap width of adjacent data recording tracks, if the total number of data recording tracks written on data surfaces does not exceed the over the top width, finding the data recording surface containing the least number of data recording tracks by determining the count values of the all data recording surfaces, and rewriting the servo patterns for defining the plurality of data recording tracks overlapped each other by the overlap width on the data recording surface found to contain the least number of data recording tracks to its read/write head, the rewriting including positioning the read/write head at one position along a radial direction of the data recording surface, rewriting servo patterns on the data recording surface by the read/write head positioned at the one position, reading the rewritten servo patterns by the read/write head positioned at the one position to detect an amplitude of output signal generated by the read/write head, moving the read/write head from the one position along the radial direction, reading the rewritten servo patterns by the read/write head moved from the one position to detect that an amplitude of output signal generated by the moved read/write head becomes 50+Y/2% of the amplitude of output signal generated by the read/write head when it is positioned at the one position, wherein the Y is the overlap width, stopping the movement of the read/write head when the detection is made, and rewriting the servo patterns on the data recording surface by the stopped read/write head stopped.
A method according to the present invention for writing servo patterns for defining a plurality of data recording tracks on each of a plurality of data recording surfaces on rotating data recording disks by a read/write head provided on each of the plurality of data recording surfaces contained is a disk drive device, includes specifying a gap width between adjacent data recording tracks, positioning the read/write head at one position along a radial direction of one data recording surface, setting a count value of a counter to an initial value, writing servo patterns on the data recording surface by the read/write head positioned at the one position, reading the servo patterns by the read/write head positioned at the one position to detect an amplitude of output signal generated by the read/write head, moving the read/write head from the one position along the radial direction, reading the servo patterns by the read/write head moved from the one position to detect that an amplitude of output signal generated by the moved read/write head becomes 50xe2x88x92Gw/2% of the amplitude of output signal generated by the read/write head when it is positioned at the one position, wherein the Gw is the specified gap width between the data recording tracks, stopping the read/write head when the detection is made, incrementing the count value, overlappingly writing the servo patterns on the data recording surface by the stopped read/write head, repeating the reading, moving, reading and stopping until the servo patterns are entirely written on the one data recording surface, electing next data recording surface and repeating the positioning, setting, writing, reading, moving, reading, stopping, incrementing, overlapping and repeating, determining whether the total number of data recording tracks written on all data recording surfaces exceeds a predetermined number, or not, specifying an overlap width of adjacent data recording tracks, if the total number of data recording tracks written on all data recording surfaces does not exceed the predetermined number, finding the data recording surface containing the least number of data recording tracks by determining the count values of the all data recording surfaces, and rewriting the servo patterns for defining the plurality of data recording tracks overlapped each other by the overlap width on the data recording surface found containing the least number of data recording tracks by its read/write head, the rewriting including positioning the read/write head at one position along a radial direction of the data recording surface, rewriting servo patterns on the data recording surface by the read/write head positioned at the one position, reading the rewritten servo patterns by the read/write head positioned at the one position to detect an amplitude of output signal generated by the read/write head, moving the read/write head from the one position along the radial direction, reading the rewritten servo patterns by the read/write head moved from the one position to detect that an amplitude of output signal generated by the moved read/write head becomes 50+Y/2% of the amplitude of output signal generated by the read/write head when it is positioned at the one position, wherein the Y is the overlap width, stopping the movement of the read/write head when the detection is made, and rewriting the servo patterns on the data recording surface by the stopped read/write head stopped.
The total number of data recording tracks written on the all data recording surfaces is determined by referring to the count values of the all data recording surfaces.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention.