Thermal Asperity Detection Skipping Tracks
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Solution Overview
Problem
Conventional thermal asperity detection methods in magnetic recording media are harmful to recording heads due to repeated contact, leading to head instability and reduced drive reliability, especially in high-density data storage systems like HAMR, where frequent contact-induced failures occur.
Innovation Solution
A method and apparatus that sense thermal asperities by scanning tracks in one direction, halting at detected asperities, skipping a predetermined number of tracks, reversing direction to re-scan, and logging the tracks between which the asperity is located, minimizing repeated contact and wear on the recording head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal asperity detection methods scan all tracks sequentially, then complete detection coverage is achieved, but repeated contact with thermal asperities causes head wear and instability
Solution Approach 1:
When a thermal asperity is detected at a current track, the method skips a predetermined number of tracks in the same direction without scanning them, then reverses direction to continue scanning. This skipping mechanism reduces repeated contact with the same thermal asperity while still achieving detection coverage across the recording medium.
Solution Approach 2:
The scanning direction is reversed after detecting a thermal asperity and skipping tracks. Instead of continuing in the original direction and repeatedly contacting the same asperity, the head reverses direction to scan remaining tracks, thereby minimizing repeated harmful contact while maintaining detection completeness.
2Reliability
If scanning continues through all tracks to ensure complete detection, then detection coverage is maximized, but drive yield and reliability decrease due to head wear
Solution Approach 1:
The method skips a predetermined number of tracks after detecting a thermal asperity, reducing the total number of scan operations required. This decreases head wear and improves drive yield while still achieving adequate detection coverage through the reverse scanning phase.
Solution Approach 2:
The detection process maintains continuity by immediately reversing direction and continuing to scan remaining tracks after skipping. This ensures that detection coverage is maintained without interruption, balancing productivity with reliability improvements.
3Measurement precision
If thermal asperities are detected by scanning each track sequentially, then accurate detection is achieved, but repeated contact events reduce operational stability
Solution Approach 1:
By skipping tracks after detecting a thermal asperity rather than scanning each track sequentially, the method reduces repeated contact events that would otherwise compromise operational stability. The reverse scanning ensures detection accuracy is maintained.
Solution Approach 2:
Reversing the scanning direction after detecting a thermal asperity prevents repeated contact with the same asperity, thereby maintaining operational stability. The inversion ensures that detection accuracy is preserved while minimizing harmful repeated interactions.
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
This approach reduces deleterious contact events with thermal asperities, enhancing drive reliability and yield by minimizing head-wear and allowing for efficient detection and classification of thermal asperities with fewer scans, thus improving the operational stability of HAMR systems.
Implementation Method 1
a thermal asperity sensor configured to sense for thermal asperities of a magnetic recording medium moving relative to the head
Data Source
AI summary
A method comprises sensing for thermal asperities while sequentially scanning a plurality of tracks of a magnetic recording medium in a first direction relative to an inner or outer diameter of the medium. The method comprises halting the scanning at a first track in response to detecting a thermal asperity at the first track, and skipping a predetermined number of tracks in the first direction to a second track. The method also comprises sensing for the thermal asperity while sequentially scanning the plurality of tracks beginning with the second track in a second direction opposite the first direction. The method further comprises halting the scanning at a third track in response to detecting the thermal asperity at the third track, and logging the first and third tracks as tracks between which the thermal asperity is located.