Multi-Sensor Transducer Head Servo Parameterization
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Solution Overview
Problem
Hard drive systems face challenges in maintaining accurate centerline tracking and format efficiency due to limitations in servo pattern parameters, leading to increased bit error rates and decreased read/write times with single-read element transducer heads.
Innovation Solution
Implementing multiple read sensors on the transducer head with manipulated servo pattern parameters based on cross-track separation to enhance servo pattern density, length, and radial spacing without compromising tracking accuracy or increasing bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-read element transducer heads are used, then device complexity is reduced, but tracking accuracy and format efficiency deteriorate
Solution Approach 1:
The transducer head is segmented into multiple independent read sensors (first read sensor and second read sensor) positioned at different cross-track separations. Each sensor independently reads servo patterns and generates position error signals, which are then combined to achieve superior tracking accuracy compared to single-sensor systems while maintaining manageable device complexity through modular sensor architecture.
Solution Approach 2:
The patent introduces a new dimension of differentiation by positioning read sensors at different cross-track separations from the data track centerline. This spatial dimensionality allows the system to capture diverse servo pattern information simultaneously, enabling enhanced tracking accuracy and format efficiency without increasing the fundamental complexity of the transducer head structure.
2Productivity
If servo pattern density is increased, then format efficiency is improved, but bit error rate increases
Solution Approach 1:
The patent applies local quality by assigning different servo pattern parameters (density, length, radial spacing) to different radial zones of the storage media. Each zone is optimized for its specific characteristics, allowing high servo pattern density in zones where multiple read sensors can effectively read without increasing bit error rates, while maintaining appropriate spacing in zones where sensors may have different performance characteristics.
Solution Approach 2:
The system dynamically adjusts servo pattern parameters including density, length, and radial spacing based on the specific zone being accessed and the cross-track separation of the read sensors. This parameter optimization allows the system to maximize format efficiency in zones where high density is beneficial while preventing bit error rate increases by adjusting parameters in zones where sensors are more susceptible to reading errors.
3Measurement precision
If multiple read sensors with different cross-track separations are used, then position error signal quality is improved, but device complexity increases
Solution Approach 1:
Multiple read sensors with different cross-track separations perform the same fundamental function of reading servo patterns and generating position error signals. This multi-functionality allows the system to achieve superior position error signal quality through sensor fusion while maintaining device complexity at a manageable level, as each sensor is a standard component performing a universal read function rather than requiring specialized complex structures.
4Measurement precision
If servo pattern length is increased, then tracking accuracy is improved, but read/write time increases
Solution Approach 1:
The patent employs partial action by using multiple read sensors to read portions of the servo pattern simultaneously at different cross-track separations. This allows the system to achieve accurate tracking with effectively shorter servo pattern lengths, as each sensor captures relevant position information from different portions of the servo sector, reducing the total read time while maintaining or improving tracking accuracy through combined position error signals.
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 format efficiency and position error signal quality while maintaining accurate centerline tracking, reducing bit error rates and read/write times without degrading storage device performance.
Implementation Method 1
one or more read sensors of the HDD reads a servo pattern from a servo sector of the data track
Data Source
AI summary
A storage media includes a plurality of servo sectors with embedded servo patterns characterized by one or more servo pattern parameters. Each of the servo sectors has a servo pattern parameter based on a separation between read sensors of a transducer head reading the servo sector.