Disk Track Spacing Uniformity via Servo Metric Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data storage devices face issues with non-uniform track spacing due to errors in servo sector writing, leading to performance degradation and unreliable data recovery, particularly for sensitive data.
Innovation Solution
A control circuitry generates a spacing metric to rewrite data tracks with more equal spacing by processing position error signals and applying corrections to the voice coil motor, ensuring accurate head positioning and improved data track alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data tracks are written using conventional servo sector methods, then data can be stored on the disk, but the track spacing becomes non-uniform leading to performance degradation and unreliable data recovery
Solution Approach 1:
The system performs preliminary measurement of actual track spacing using servo sector information before the main data writing process. This preliminary action allows the system to establish a spacing metric and correction factors in advance, ensuring that subsequent data tracks are written with uniform spacing despite servo sector non-uniformity
Solution Approach 2:
The system continuously monitors track spacing by reading servo sector information and generates feedback signals. This feedback is used to dynamically adjust the head positioning and writing parameters, compensating for spacing variations and maintaining uniform track spacing throughout the data storage process
2Ease of operation
If servo sectors are written with standard methods, then head positioning information is available, but errors in servo writing cause non-uniform track spacing
Solution Approach 1:
The system introduces an intermediary spacing metric that decouples the relationship between servo sector positioning and actual data track spacing. This intermediary measurement layer allows the system to use servo sectors for head positioning while independently controlling and measuring the actual spacing between data tracks, filtering out servo writing errors
Solution Approach 2:
The system dynamically changes writing parameters such as head positioning offsets and writing timing based on measured spacing variations. By adjusting these parameters in real-time, the system compensates for servo sector non-uniformity and maintains consistent data track spacing
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
The solution enhances data recovery reliability by achieving more uniform data track spacing, independent of servo track non-uniformity, thereby improving the quality and integrity of stored data.
Implementation Method 1
a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM) to position the head radially over the disk
Implementation Method 2
The servo sectors comprise head positioning information (e.g., a track address) which is read by the head and processed by a servo control system
Data Source
AI summary
A data storage device is disclosed comprising a head actuated over a disk. A plurality of data tracks on the disk are first written, and a metric representing a spacing between at least two of the first written data tracks is generated. At least two of the plurality of data tracks are rewritten based on the generated metric such that the rewritten data tracks comprise a more equal spacing compared to the first written data tracks.