Magnetic Disk Read Head Offset Adjustment Under Vibration
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Solution Overview
Problem
Magnetic disk devices face challenges in accurately reading data due to tilting of the head, leading to errors in track positioning and increased error rates when the read head is not optimally aligned with the write head, especially under vibration conditions.
Innovation Solution
The magnetic disk device employs a controller to adjust the read head's offset during read processing based on vibration states, positioning it at either the target read radial position or the correction read radial position to minimize error rates, depending on the presence of vibrations and tilting angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the read head is positioned at the target read radial position based on fixed offset from write head, then the device structure is simple, but read error rate increases under vibration conditions
Solution Approach 1:
The patent applies dynamics by making the read head radial position adjustable rather than fixed. The controller dynamically changes the offset amount between write head and read head radial positions based on vibration conditions, allowing the system to adapt to varying operational environments and maintain reliable reading performance.
Solution Approach 2:
The patent changes the parameter of offset amount between write head and read head radial positions. By adjusting this parameter based on vibration detection, the system optimizes read performance under different conditions without requiring complete repositioning of the head assembly.
2Measurement precision
If the read head offset is fixed regardless of vibration, then the control system is simple, but track positioning accuracy deteriorates under vibration
Solution Approach 1:
The patent implements feedback by detecting vibration conditions and using this information to adjust the read head offset. The controller receives vibration status feedback and automatically modifies the radial position offset to maintain accurate track positioning despite vibration-induced head tilting.
Solution Approach 2:
The patent applies preliminary anti-action by proactively adjusting the read head offset before reading operations when vibration is detected. The controller predicts potential positioning errors due to vibration and compensates by changing the offset amount in advance, preventing track positioning inaccuracies.
3Reliability
If the read head is always positioned at correction read radial position to handle vibration, then read performance under vibration improves, but normal read performance may be reduced and device complexity increases
Solution Approach 1:
The patent uses dynamics by conditionally adjusting the read head position based on real-time vibration detection. During normal operation without vibration, the read head maintains its standard radial position for optimal performance. When vibration is detected, the controller dynamically shifts the read head to the correction radial position, ensuring high reliability only when needed.
Solution Approach 2:
The patent changes the offset parameter conditionally based on vibration status. The controller monitors vibration levels and adjusts the radial offset between write and read heads only when vibration thresholds are exceeded, maintaining normal read performance during standard operations while improving reliability under vibrational stress.
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk, a head that has a write head that writes data to the disk and a read head that reads data from the disk, and a controller that changes an offset amount during read processing according to a vibration applied by a disturbance.