Magnetic Disk Servo Pattern Recording Condition Optimization
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Solution Overview
Problem
Magnetic disk devices face challenges in setting optimal recording conditions, leading to excessive recording quality in some areas and potential reliability issues due to uniform recording conditions based on the most difficult recording area's characteristics.
Innovation Solution
A magnetic disk device that utilizes a servo pattern with recording quality determination data to adjust the track recording density for each sector, allowing for personalized recording conditions based on the servo pattern, thereby optimizing data recording quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recording condition is determined on the basis of the characteristics of the recording area most difficult to record of all the recording areas in the circumference, then the data recording quality in one circumference is guaranteed, but the recording condition becomes excessive in other areas leading to excessive recording quality
Solution Approach 1:
The patent applies local quality by setting different recording conditions for different recording areas based on their specific characteristics. The control section determines recording conditions individually for each recording area using servo patterns written in advance, rather than using a uniform condition for the entire circumference. This allows each area to have optimized recording conditions matched to its local magnetic characteristics, resolving the contradiction between guaranteeing minimum quality and avoiding excessive conditions.
2Manufacturing precision
If a test pattern is written and the writing quality is evaluated to change the current waveform for each sector, then the recording condition can be optimized, but an area configured to store the test pattern and processing for evaluation become necessary
Solution Approach 1:
The patent makes the servo pattern multi-functional by using it for both positioning purposes and recording quality evaluation. The same servo pattern that is already written for head positioning is also used to determine recording conditions, eliminating the need for separate test patterns and their associated storage areas. This resolves the contradiction by making the existing servo infrastructure serve dual purposes.
Solution Approach 2:
The patent extracts the recording quality evaluation function from the test pattern writing process and integrates it into the servo pattern utilization. By taking out the evaluation function and combining it with the positioning function in a single servo pattern system, the patent eliminates redundant test pattern storage and processing requirements while maintaining optimization capabilities.
3Manufacturing precision
If the recording density is changed according to the distribution in the circumference of the medium examined in advance, then the recording quality can be optimized, but when the recording density is made excessively high, a case where a problem in the reliability of data occurs is conceivable
Solution Approach 1:
The patent changes recording parameters (recording density and/or recording condition) based on the evaluated characteristics of each recording area. By adjusting these parameters individually for each area using servo pattern information, the system achieves optimized recording quality without excessively increasing density in areas where it is not needed, thus maintaining data reliability while improving overall recording performance.
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 improves data recording quality by equalizing bit error rate distributions across sectors, reducing fluctuations, and maintaining sufficient recording capacity, resulting in higher overall surface recording density.
Implementation Method 1
A magnetic disk device includes a magnetic head, a magnetic disk on which a servo pattern used to position the magnetic head when data is to be recorded by means of the magnetic head is recorded
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a magnetic head, a magnetic disk on which a servo pattern used to position the magnetic head when data is to be recorded by means of the magnetic head is recorded, and a control section configured to set a recording condition for each predetermined unit of the magnetic disk on the basis of the servo pattern, and carry out recording of data on the magnetic disk according to the set recording condition.