Disk Drive Read Element Spacing and Radial Band Configuration
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Solution Overview
Problem
Existing disk drive technologies face challenges in accurately positioning the head over data tracks due to inter-track interference (ITI) and varying skew angles, which affect data detection and recording density, especially when using multiple read elements with potential manufacturing tolerances and varying radial densities.
Innovation Solution
Implementing a disk drive system with at least three read elements that dynamically switch between one-dimensional and two-dimensional demodulation algorithms based on the head's radial location, using measured spacing and skew angles to compensate for ITI and optimize track pitch, thereby improving data detection accuracy and recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple read elements are used to increase data detection accuracy, then data detection accuracy is improved, but inter-track interference increases due to varying skew angles and manufacturing tolerances
Solution Approach 1:
The disk surface is divided into multiple radial bands, with each band containing a specific number of tracks. The system segments the recording area into one-dimensional areas (single radial band) and two-dimensional areas (multiple radial bands), allowing different detection methods to be applied to different segments based on their ITI characteristics
Solution Approach 2:
The patent transitions from traditional one-dimensional track-by-track detection to two-dimensional detection by accessing multiple radial bands simultaneously. This dimensional change allows the system to compensate for ITI by utilizing data from adjacent tracks in different radial bands, effectively resolving the interference problem while maintaining high detection accuracy
2Quantity of substance
If higher radial density is implemented to increase recording capacity, then recording density is improved, but head positioning accuracy deteriorates due to increased sensitivity to skew angles and read element spacing variations
Solution Approach 1:
The system dynamically adjusts detection parameters based on the radial band being accessed. By changing the detection methodology (one-dimensional vs. two-dimensional) and adjusting equalization parameters according to the radial position, the system maintains optimal head positioning accuracy across different radial densities while maximizing recording capacity
3Device complexity
If one-dimensional detection method is used to simplify processing, then device complexity is reduced, but data detection accuracy deteriorates in high-density radial areas due to ITI
Solution Approach 1:
The system dynamically selects between one-dimensional and two-dimensional detection methods based on the current radial band and ITI conditions. In low-density areas where ITI is minimal, simple one-dimensional detection is used. In high-density areas where ITI is significant, the system transitions to two-dimensional detection, optimizing the balance between processing complexity and detection accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances data detection accuracy and recording density by effectively compensating for ITI and optimizing track pitch, allowing for higher data capacity and reliability across different radial bands.
Implementation Method 1
A read element (e.g., a magnetoresistive (MR) element) is then used to transduce the magnetic transitions into a read signal that is demodulated by a read channel
Data Source
AI summary
A disk drive is disclosed comprising a disk comprising a plurality of tracks, and a head comprising a first read element and a second read element. A spacing of the first and second read elements is measured, and based on the measured spacing, the tracks are grouped into radial bands that define at least one one-dimensional recording area on the disk and at least one two-dimensional recording area on the disk. When the head is within a first two-dimensional recording area, data recorded on the disk is detected by processing a first read signal generated by the first read element and by processing a second read signal generated by the second read element using a two-dimensional demodulation algorithm. When the head is within a first one-dimensional recording area, data recorded on the disk is detected by processing the first read signal using a one-dimensional demodulation algorithm.