Patterned Media Servo Zones with Overlap and Bootstrap Regions
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Solution Overview
Problem
Existing servo writing technologies face challenges in writing servo data across servo zone boundaries on patterned magnetic disks, particularly in maintaining uniformity and compatibility with planarization constraints, which affect the alignment and accuracy of slider positioning over the disk.
Innovation Solution
The implementation of a zoned servo architecture with alternating series of concentric servo zones and overlap zones, where overlap zones are dual frequency zones with patterns identical to bordering zones, and bootstrap zones assist initial servo writing, allowing for robust servo data writing across zone boundaries while complying with planarization constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a zoned servo architecture with alternating servo zones and overlap zones is implemented, then servo data writing accuracy across zone boundaries is improved, but device complexity increases due to dual frequency zones and bootstrap zones
Solution Approach 1:
The disk surface is segmented into multiple servo zones with different servo frequencies, separated by overlap zones. This segmentation allows each zone to be optimized for its specific radial position while overlap zones provide transition regions that maintain continuity across zone boundaries, resolving the contradiction between precision and complexity.
Solution Approach 2:
Overlap zones act as intermediary regions between servo zones of different frequencies. These zones contain patterns from both adjacent servo zones, serving as a transition buffer that enables accurate servo data writing across zone boundaries without requiring complex real-time frequency switching, thus improving precision while managing complexity.
2Stability of the object's composition
If overlap zones with dual frequency patterns are used, then alignment continuity across servo zone boundaries is improved, but data capacity is reduced due to the space required for overlap zones
Solution Approach 1:
The disk is divided into servo zones and overlap zones, with overlap zones occupying a small radial portion. This segmentation allows alignment continuity to be maintained in the overlap regions while minimizing the space consumed, thus preserving data capacity in the majority of the disk surface.
Solution Approach 2:
The servo frequency parameter is changed across different zones, with overlap zones containing patterns from both adjacent frequencies. This parameter transition enables alignment continuity while the radial extent of overlap zones is optimized to minimize data capacity loss.
3Reliability
If bootstrap zones are implemented to assist initial servo writing, then reliability of servo writing process is improved, but manufacturing time increases due to additional writing steps
Solution Approach 1:
Bootstrap zones are pre-written with initial servo patterns before the main servo writing process. This preliminary action provides a reliable starting point for self-servo writing, ensuring accurate track following from the inner diameter outward, which improves reliability while the automated propagation minimizes additional manufacturing time.
Solution Approach 2:
The bootstrap zones enable the servo writing system to be self-sufficient by providing initial patterns that allow the write head to automatically propagate servo data across the disk without requiring continuous external intervention, improving reliability while streamlining the manufacturing process.
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 enables accurate and efficient servo data writing across servo zone boundaries, maintaining alignment and data integrity, and enhances data capacity by accommodating varying radial overlap lengths and frequencies, thus improving the robustness of servo writing on patterned media.
Implementation Method 1
The servo sectors include servo data that is used to position the slider. Servo data is typically only written at the manufacturing facility and cannot be changed by the end-user.
Implementation Method 2
Both the data regions and servo sectors can include information that is magnetically written by the write head onto the magnetic disk and also read back by the read head from the magnetic disk.
Data Source
AI summary
Embodiments described herein provide for patterned media concentric zones with an alternating series of concentric servo zones and overlap zones. The overlap zones facilitate the writing of servo data between servo zones of different servo frequency. The overlap zones may be dual frequency zones. The dual frequency zones have a first set of overlap patterns with the substantially identical pattern as the bordering lower frequency servo zone and a second set of overlap patterns with the substantially identical pattern as the bordering higher frequency servo zone. A bootstrap zone can be included near the inner diameter to assist initial servo writing. Alternatively the overlap zones are bootstrap zones. Such bootstrap zones have both bootstrap patterns and overlap patterns, the overlap patterns have the substantially identical pattern as a bordering servo zone. Bootstrap patterns only require DC magnetization for servo operability.