Write Coil Stabilization for HAMR Reader Instability
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Solution Overview
Problem
Magnetic reader instability induced by previous write operations leads to increased bit error rate (BER) during data reading in heat-assisted magnetic recording (HAMR) devices, causing sector failures and requiring lengthy error recovery procedures that may not always be effective.
Innovation Solution
Activating the write coil of the read/write head with a small or zero laser power to produce a magnetic field that re-stabilizes the reader, allowing for immediate re-reading of data without overheating the recording medium, thus addressing reader instability and reducing BER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the write coil is activated to re-stabilize the reader, then reader stability is improved, but there is a risk of overheating the recording medium and changing data state
Solution Approach 1:
The write coil is activated with reduced current or for a shorter duration than normal write operations, providing just enough magnetic field to stabilize the reader without generating sufficient heat to alter the magnetic state of the recording medium. This partial action achieves the stabilization goal while avoiding the harmful overheating effect.
Solution Approach 2:
The patent changes the operational parameters of the write coil, specifically reducing the current magnitude or pulse width during the stabilization phase. This parameter modification allows the write coil to perform its stabilizing function on the reader while keeping the thermal impact on the recording medium below the threshold for data state changes.
2Reliability
If traditional error recovery procedures are used, then read errors may be corrected, but the recovery time is lengthy and may not always be effective
Solution Approach 1:
The write coil is activated in advance during the traversal of the recording medium, before the read head encounters the unstable sector. This preliminary stabilization action prevents the reader instability from occurring in the first place, enabling immediate successful re-reading without requiring lengthy traditional error recovery procedures.
Solution Approach 2:
Instead of allowing the read head to slowly traverse and repeatedly attempt to read the unstable sector, the patent rushes through the stabilization process by activating the write coil during the same disk revolution, enabling recovery within one or two revolutions rather than requiring multiple slow retry cycles.
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 method effectively reduces bit error rate and enables quick recovery from read errors by stabilizing the reader without overwriting data, completing the process within one or two revolutions of the disk, thereby improving data storage reliability and efficiency.
Implementation Method 1
writing to a recording medium using a read/write head with an energy source that heats the media during the writing
Implementation Method 2
Activating the write coil of the read/write head with a small or zero laser power to produce a magnetic field that re-stabilizes the reader
Implementation Method 3
The activation of the write coil removes a magnetic instability of the read transducer
Data Source
AI summary
A recording medium is written to using an energy source that heats the medium during the writing. A read error in a sector is determined when reading via a read transducer. While traversing a part of the recording medium that includes data, a write coil is activated before attempting to re-read the sector. The energy source does not heat the recording medium sufficiently to change a state of the data during the activation of the write coil. The activation of the write coil removes a magnetic instability of the read transducer.