Data storage disk with information encoded in the position error signal fields
First Claim
1. A data storage disk comprising:
- a substrate;
a magnetic recording medium deposited on the substrate; and
a plurality of position error signals recorded on the magnetic recording medium, the position error signals having at least first and second groups with the first group of position error signals being angularly offset from the second group of position error signals, the first group being positioned on a centerline of a track and the second group being offset from the centerline of the track, each position error signal (PES) being a set of magnetic transitions, each set of magnetic transitions representing binary data which is a function of a track number where the PES is located, the binary data including redundancy bits which provide a first error detecting scheme for reading errors, the binary data being further composed of a plurality of bit-vectors which correspond to symbols having fewer bits than the bit-vectors which creates a mapping providing a second error detecting scheme.
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Accused Products
Abstract
There is disclosed a disk for use in a disk drive and a method for making the disk. The position error signal (PES) fields for each track on the disk are written with predetermined data, e.g. servo data, encoded thereon. In the preferred embodiment: a) the data such as the track number is mapped into codewords of an error correction code (ECC); b) bit-vectors are used to encode the symbols for further redundancy; and c) the raw data written in the PES fields is constrained to equalize the analog signal characteristic used by the servo system for positioning. Thus, the invention allows the PES fields to be used as in the prior art while also being used as a source of digital data which is robustly recorded therein. In one aspect of the invention, the track ID'"'"'s are written in the PES fields in a selected pattern in which the track ID for each track is recorded in two PES field groups. One of the two PES field groups is centered on the selected track while the other PES field group is offset so that it partially overlaps the adjacent track, as well as the selected track. The PES fields will typically be recorded on the disk at the time of manufacture and not changed thereafter.
14 Citations
16 Claims
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1. A data storage disk comprising:
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a substrate; a magnetic recording medium deposited on the substrate; and a plurality of position error signals recorded on the magnetic recording medium, the position error signals having at least first and second groups with the first group of position error signals being angularly offset from the second group of position error signals, the first group being positioned on a centerline of a track and the second group being offset from the centerline of the track, each position error signal (PES) being a set of magnetic transitions, each set of magnetic transitions representing binary data which is a function of a track number where the PES is located, the binary data including redundancy bits which provide a first error detecting scheme for reading errors, the binary data being further composed of a plurality of bit-vectors which correspond to symbols having fewer bits than the bit-vectors which creates a mapping providing a second error detecting scheme. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A data storage disk comprising:
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a substrate; a magnetic recording medium deposited on the substrate; and a plurality of position error signals recorded on the magnetic recording medium, the position error signals having at least first, second, third and fourth groups with each group of position error signal (PES) having a uniquely identifying angular offset from a servo index marker, the first and third groups of PES being respectively positioned on centerlines of alternate tracks and the second and fourth groups of PES being offset from centerlines of the tracks, each PES being a set of magnetic transitions, each set of magnetic transitions representing binary data which is a function of a concentric track number where the PES is located, the binary data including redundancy bits for detecting reading errors, the binary data being further composed of a plurality of n-bit vectors which map to a plurality of symbols having n-1 or less bits per symbol, the binary data for the first and second PES groups containing information which identifies the track on which the first PES group is centered and the binary data for the third and fourth PES groups containing information which identifies the track on which the third PES group is centered. - View Dependent Claims (12, 13)
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14. A method of making a data storage disk having a magnetic recording medium comprising the steps of:
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encoding a track identifier n in a first codeword which includes redundancy bits; dividing the first codeword into a first set of one or more symbols; mapping the first set of one or more symbols into a set of bit-vectors having more bits per vector than the number of bits in a symbol; and writing the the bit-vectors in a plurality of position error signals at selected radial positions on the magnetic recording medium. - View Dependent Claims (15, 16)
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Specification