Magnetic Disk Device On-Track Determination Number Adjustment
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Solution Overview
Problem
Magnetic disk devices face challenges in accurately determining the on-track state of a magnetic head after seeking, leading to potential write quality issues due to variations in the head's position and speed.
Innovation Solution
A method is implemented where a processing unit acquires feature amounts from the position error between the demodulated and estimated positions of the magnetic head, using frequency resonance characteristics or vibration frequency, to set an on-track determination number, which confirms the head's on-track state by predicting variations in position and adjusting the determination criteria accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the on-track determination number is fixed regardless of seek variation, then the device complexity is reduced, but the write quality deteriorates when position variations are large
Solution Approach 1:
The patent makes the on-track determination number dynamic by adjusting it based on the magnitude of position variation detected during seeking. When position variation is large, the determination number is increased to ensure adequate stabilization time; when variation is small, the number is reduced to improve efficiency. This dynamic adjustment resolves the contradiction between maintaining write quality and avoiding excessive device complexity.
Solution Approach 2:
The patent changes the parameter of on-track determination number based on detected position variation characteristics. By monitoring position error during seeking and adjusting the determination number accordingly, the system adapts to different seeking conditions, ensuring write quality without requiring a fixed high number that would increase overall system complexity.
2Manufacturing precision
If the on-track determination number is increased to ensure stability, then the write quality is improved, but the productivity decreases due to longer determination time
Solution Approach 1:
The patent dynamically adjusts the on-track determination number based on actual position variation during seeking. When position stability is already high, the determination number is reduced, allowing faster writing without compromising quality. When variation is large, the number is increased to ensure stability. This dynamic approach resolves the contradiction between write quality and productivity.
Solution Approach 2:
The system changes the determination number parameter adaptively based on position error characteristics. By monitoring position variation and adjusting the parameter accordingly, the system achieves optimal balance between write quality assurance and writing speed, preventing unnecessary delays when stability is already sufficient.
3Productivity
If the on-track determination number is decreased for faster writing, then the productivity is improved, but the reliability decreases when position variations are large
Solution Approach 1:
The patent makes the determination number dynamic, increasing it when position variation is large to maintain reliability, and decreasing it when variation is small to improve productivity. This dynamic behavior ensures that reliability is maintained under critical conditions while productivity is optimized under stable conditions.
Solution Approach 2:
The system adjusts the determination number parameter based on position error magnitude. When position variation exceeds thresholds, the parameter is increased to ensure reliable on-track confirmation; when variation is within acceptable ranges, the parameter is reduced to enable faster writing, thus maintaining reliability while improving productivity.
4Ease of operation
If the on-track determination is performed with fixed criteria, then the ease of operation is improved, but the adaptability to different seek conditions deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the determination number based on position variation characteristics during seeking. This maintains ease of operation through automated adjustment while achieving adaptability to different seek conditions, resolving the contradiction between operational simplicity and conditional adaptability.
Solution Approach 2:
The system changes the determination number parameter adaptively based on position error during seeking, maintaining ease of operation through automated control while achieving versatility across different seek scenarios. The parameter adjustment is transparent to operators, preserving ease of use while enhancing adaptability.
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 allows for delayed writing until the magnetic head's position and speed are stabilized, preventing write quality deterioration when variations are large, while enabling faster writing when variations are small, thus optimizing the on-track determination process.
Implementation Method 1
a magnetic head accesses a magnetic disk
Implementation Method 2
an actuator causes the magnetic head to seek on the magnetic disk
Data Source
AI summary
According to an embodiment, a magnetic disk, a magnetic head, an actuator and a processing unit are provided. The processing unit acquires a feature amount from a position error between a demodulated position and an estimated position of the magnetic head based on a frequency resonance characteristic of the actuator or a frequency characteristic of vibration caused by disturbance of the actuator and, based on the feature amount, sets an on-track determination number used for confirming an on-track state of the magnetic head after seeking.