Interlaced Magnetic Recording Head Write Order
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Solution Overview
Problem
As data storage density increases, reducing cell size in magnetic media poses challenges in writing data without affecting adjacent cells, as a strong write field gradient is needed, leading to potential overwriting of adjacent data in smaller cells, which is mitigated by interlaced magnetic recording (IMR) but faces complexities in manufacturing and laser power management.
Innovation Solution
A storage device with a magnetic recording head and controller that writes data tracks with uniform width, using a prioritized write order where alternating tracks have slightly overlapping edges, allowing for increased linear density without degrading adjacent tracks, achieved through consistent write current parameters and potentially varying laser power in HAMR devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a strong write field gradient is used to shift the polarity of cells, then writing data to smaller cells becomes possible, but adjacent cells may be overwritten
Solution Approach 1:
The patent divides the write operation into two separate passes: a first write pole writes to one set of alternating tracks, and a second write pole writes to the interlaced tracks. This segmentation allows each pole to be optimized for its specific track set, enabling smaller cell sizes without adjacent cell overwriting because each pole's field is confined to its designated tracks.
Solution Approach 2:
The patent introduces an intermediary structure - the interlaced track pattern itself - that mediates between the write field and the storage cells. By organizing tracks into alternating and interlaced sets, the system creates a buffer zone that prevents the strong write field gradient from affecting adjacent cells, allowing high-density writing without data corruption.
2Manufacturing precision
If interlaced magnetic recording is implemented to prevent adjacent data overwriting, then smaller cells can be used, but manufacturing complexity increases
Solution Approach 1:
The write head is segmented into two independent write poles, each responsible for a specific set of alternating tracks. This segmentation simplifies manufacturing compared to traditional IMR because each pole can be independently optimized and assembled, reducing the complexity of creating a single complex multi-element writer while still achieving the benefits of interlaced recording.
Solution Approach 2:
The patent uses uniform write current parameters for both write poles, creating homogeneous operating conditions. This homogeneity simplifies the control electronics and manufacturing process, as the same current driving circuitry can be used for both poles, reducing the complexity associated with implementing interlaced magnetic recording.
3Manufacturing precision
If alternating tracks are written first before interlaced tracks, then uniform written track width is achieved, but write time increases
Solution Approach 1:
The controller is configured to perform preliminary writing to the alternating tracks using the first write pole before activating the second write pole for the interlaced tracks. This preliminary action ensures uniform written track width by establishing a consistent writing pattern first, while the overlapping alternating track design minimizes the additional time required compared to sequential track-by-track writing.
Solution Approach 2:
The patent implements periodic alternating writing between the two write poles, switching between writing to alternating tracks and interlaced tracks in a regular pattern. This periodic action maintains uniform written track width across all tracks while optimizing write time by keeping both poles actively engaged in a coordinated manner rather than sequentially.
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 enhances areal density capacity while maintaining system performance and reducing adjacent track interference, achieving higher linear density without the drawbacks of variable track widths or complex manufacturing processes.
Implementation Method 1
a write pole for converting a series of electrical pulses sent from a controller into a series of magnetic pulses of commensurate magnitude and length. The magnetic pulses of the write pole selectively magnetize magnetic grains of the storage medium
Implementation Method 2
in Heat-Assisted Magnetic Recording (HAMR) devices, by varying laser power on alternating data tracks
Implementation Method 3
Heat-Assisted Magnetic Recording (HAMR) devices, by varying laser power on alternating data tracks
Data Source
AI summary
A storage device includes a storage medium, a magnetic recording head, and a controller configured to operate the magnetic recording head to write consecutive data tracks at a uniform written track width and further configured to write data to alternating data tracks of the consecutive data tracks prior to writing data to at least one track interlaced with the alternating data tracks.