Magnetic Disk Recording Density Zonal Optimization
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Solution Overview
Problem
Magnetic disk devices face challenges in achieving uniform recording quality due to variations in manufacturing quality, leading to inconsistencies in bit error rates across different positions on the recording surface, which are not adequately addressed by existing methods.
Innovation Solution
A method for setting recording density by dividing the recording surface into zones and individually adjusting the linear and track densities based on areal margins, ensuring that each zone has a uniform and maximized areal margin, thereby ensuring consistent quality and tolerance to overwriting and bit error rate variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform linear and track densities are set across the entire recording surface, then the device complexity is reduced, but the recording quality becomes non-uniform due to manufacturing variations
Solution Approach 1:
The recording surface is divided into multiple zones (first zone, second zone, etc.) along the radial direction. Each zone is independently assigned linear and track densities to compensate for manufacturing variations. This segmentation allows different recording parameters to be applied to different regions, ensuring uniform recording quality across the entire surface while managing complexity through systematic zonal classification.
Solution Approach 2:
Different linear and track densities are assigned to different zones based on their specific characteristics and manufacturing variations. The first zone has different recording densities compared to the second zone, allowing each region to be optimized for its local conditions. This local quality approach ensures that each zone achieves optimal recording quality tailored to its specific manufacturing characteristics.
2Quantity of substance
If higher linear recording density is used, then the storage capacity increases, but the tolerance to overwriting and bit error rate variations decreases
Solution Approach 1:
The invention changes the recording density parameters (linear and track densities) across different zones to optimize the balance between storage capacity and reliability. By adjusting these parameters systematically across zones, the system achieves high overall capacity while maintaining adequate tolerance to overwriting and bit error rate variations in each specific zone.
Solution Approach 2:
The invention applies higher linear recording densities in certain zones where it is feasible, while maintaining lower densities in zones where reliability is more critical. This partial application of high density allows the system to maximize overall capacity without compromising the reliability requirements in all zones, achieving an optimal balance through selective density assignment.
3Manufacturing precision
If the areal margin is increased to improve quality, then the recording quality and tolerance to variations improve, but the effective storage capacity decreases
Solution Approach 1:
The invention segments the recording surface into zones with different areal margin requirements. By dividing the surface, the system can apply larger areal margins only in zones where quality consistency is most critical, while using smaller margins in zones where capacity is prioritized. This segmented approach optimizes the overall balance between quality and capacity.
Solution Approach 2:
Different areal margins are applied locally to different zones based on their specific requirements. Some zones receive larger areal margins to ensure quality consistency, while other zones use smaller margins to maximize capacity. This local differentiation allows the system to achieve quality consistency where needed without unnecessarily reducing overall storage capacity.
Data Source
AI summary
According to one embodiment, a recording density setting method includes performing first process and performing second process. The first process including recording and reading data on and from a disk medium of a magnetic disk device, and acquiring first information for setting the read data to satisfy a certain quality criterion. The first information represents a first shape of a first plurality of unit regions. Each of the a first plurality of unit regions is a recording region of a unit capacity. The second process includes acquiring second information representing a second shape of the first plurality of unit regions, and setting a recording density on the basis of the second information. The second shape is formed by adding margin regions having the same area to the first plurality of unit regions of the first shape.