Magnetic Disk Head Settling Count Adaptation
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Solution Overview
Problem
Existing magnetic disk apparatuses face challenges in determining the optimal settling count for residual vibration attenuation, leading to potential write operation interruptions due to insufficient vibration attenuation or increased seek times from overly large settling counts.
Innovation Solution
The magnetic disk apparatus autonomously determines the settling count by estimating the frequency and amplitude of residual vibrations during the settling operation, updating the settling count based on these estimates to ensure sufficient vibration attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large settling count is used to ensure sufficient vibration attenuation, then write operation reliability is improved, but seek time increases
Solution Approach 1:
The settling count is changed from a fixed value to a dynamically adjustable parameter based on actual residual vibration characteristics. The controller estimates vibration frequency and amplitude, then adaptively determines the settling count to match the actual attenuation requirements, allowing optimization between reliability and time for each seek operation.
Solution Approach 2:
The patent changes the parameter of settling count from a static predetermined value to a dynamic value determined by vibration estimation. By calculating the relationship between vibration frequency/amplitude and required settling count, the system adjusts this parameter in real-time to prevent both over-settling (wasting time) and under-settling (causing write interruptions).
2Productivity
If a small settling count is used to reduce seek time, then productivity is improved, but write operation reliability deteriorates due to insufficient vibration attenuation
Solution Approach 1:
The system implements feedback by estimating residual vibration characteristics (frequency and amplitude) after each seek operation and using this information to determine the appropriate settling count. This closed-loop approach ensures that the settling count is neither too large (reducing productivity) nor too small (compromising reliability), but optimally matched to actual conditions.
Solution Approach 2:
The magnetic disk apparatus performs self-diagnosis by autonomously estimating its own residual vibration characteristics and automatically adjusting the settling count without external intervention. This self-service mechanism enables real-time optimization of the settling period based on actual system state, improving both productivity and reliability.
Data Source
AI summary
According to an embodiment, a controller of a magnetic disk apparatus moves a magnetic head to a first track being one of tracks on a magnetic disk. The controller acquires, in a servo sampling cycle, a positioning error amount of the magnetic head with respect to the first track. The controller executes an access to the first track by the magnetic head after a positioning error amount equal to or less than a first threshold is continuously acquired a first set number of times. The controller obtains a frequency estimation value by estimating a frequency of residual vibration of the magnetic head due to movement of the magnetic head to the first track and obtains an amplitude estimation value by estimating an amplitude of the residual vibration. The controller updates the first set number of times on the basis of the frequency estimation value and the amplitude estimation value.