Magnetic Disk Servo Pattern Detection for Accurate Head Positioning
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Solution Overview
Problem
In magnetic disk devices, invalid regions without post codes are mistakenly read as valid, leading to incorrect magnetic head positioning due to the absence of meaningful information, which affects data alignment on tracks.
Innovation Solution
The magnetic disk device incorporates a controller that distinguishes between first and second physical patterns in servo regions, determining the presence of a third servo region using a magnetic head, and employs a method to differentiate between post codes and base patterns through read waveform analysis, utilizing correlation coefficients to enhance positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the magnetic head uses post code reading for track alignment, then positioning speed is improved, but positioning accuracy deteriorates due to erroneous reading of invalid regions
Solution Approach 1:
The system performs preliminary classification of servo regions into valid post code regions and invalid base pattern regions before using them for positioning. By pre-identifying which regions contain meaningful post code information and which are invalid, the system avoids using invalid regions for alignment, thus maintaining both fast positioning speed and high positioning accuracy.
Solution Approach 2:
The system introduces an intermediary classification mechanism that distinguishes between valid post code regions and invalid base pattern regions. This intermediary step prevents direct misinterpretation of invalid regions as valid post codes, resolving the contradiction between speed and accuracy by ensuring only valid regions are used for positioning while maintaining efficient operation.
2Productivity
If the system reads all servo regions as post codes, then data processing speed is improved, but data reliability deteriorates due to inclusion of invalid information
Solution Approach 1:
The servo regions are segmented into valid post code regions and invalid base pattern regions. This segmentation allows the system to process only valid regions for positioning information, excluding invalid regions from processing. The result is maintained high data processing speed while ensuring data reliability by preventing inclusion of invalid information in positioning calculations.
Solution Approach 2:
The system extracts and identifies valid post code regions from the mixture of valid and invalid servo regions. By taking out only the valid post code-containing regions for processing and excluding invalid base pattern regions, the system maintains high productivity while ensuring reliability through selective processing of only meaningful data.
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 magnetic head positioning accuracy by accurately identifying valid post codes, reducing errors in track alignment and enhancing data reading and writing efficiency.
Implementation Method 1
a magnetic head that performs data reading and data writing on the magnetic disk
Data Source
AI summary
A magnetic disk device according to an embodiment includes: a magnetic disk including a plurality of tracks; a magnetic head that performs data reading and data writing on the magnetic disk; a plurality of servo regions that is provided in each of the plurality of tracks, and at least partially includes a first physical pattern, the first physical pattern being a physical pattern after writing of a first data pattern including position information of each of the plurality of tracks; and a controller that controls the magnetic head, wherein the plurality of servo regions includes one of a first servo region including the first physical pattern, and a second servo region including a second physical pattern, the second physical pattern being a physical pattern after writing of a second data pattern different from the first data pattern, for each of the plurality of tracks, and the controller performs determination as to which of the first and second physical patterns a third servo region has, the third servo region being one of a servo region among the plurality of servo regions included in the plurality of tracks.