Hybrid Magnetic Disk Write Control for Adjacent Track Errors
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Solution Overview
Problem
Magnetic disk devices face challenges in managing data write operations across adjacent data tracks, particularly in hybrid recording systems, where conventional and shingled magnetic recording techniques are combined, leading to issues with track-based error correction and positioning errors that affect data integrity and storage efficiency.
Innovation Solution
A magnetic disk device with a hybrid recording capability, incorporating a buffer memory system that manages data write operations by selectively executing track-based error correction and adjusting overwrite policies based on positioning errors, using a correction limit discrimination unit to optimize data management and storage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If track-based error correction is executed for data on a first track while writing to an adjacent second track, then data integrity on the first track is improved, but positioning errors increase due to head movement and seek operations
Solution Approach 1:
The patent dynamically adjusts the error correction strategy based on the positioning error magnitude. When positioning error exceeds a threshold, the system switches from executing error correction for the first track to allowing overwrite of buffered data for the first track, thereby adapting the data management approach to current positioning conditions and preventing further data degradation
Solution Approach 2:
The system performs preliminary actions by buffering data for the first track before positioning errors occur. When positioning error exceeds the threshold, the buffered data can be overwritten without loss, as the preliminary buffering had already captured the data. This preliminary data capture enables flexible response to positioning errors
2Productivity
If the write head is positioned to write data to the second track, then storage efficiency is improved, but positioning errors occur that affect data writing to the first track
Solution Approach 1:
The buffer memory acts as an intermediary between the write head and the first track data. Data for the first track is stored in the buffer, allowing the write head to freely position to the second track for writing without concern for positioning errors affecting the first track. The buffer mediates the decoupling of write operations from positioning constraints
3Productivity
If data in the buffer memory is overwritten to improve write speed, then productivity is improved, but data integrity is compromised when positioning errors occur
Solution Approach 1:
The system continuously monitors positioning error magnitude and uses this feedback to control buffer management decisions. When positioning error exceeds the threshold, the system feedback-indicates that overwrite should be permitted; when below the threshold, overwrite is prohibited. This feedback mechanism ensures write speed optimization only occurs when positioning conditions are safe
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
Enhances data integrity and storage efficiency by minimizing positioning errors and optimizing data write operations across adjacent tracks, ensuring effective error correction and efficient use of buffer memory resources.
Implementation Method 1
a write head writing data to a recording layer
Implementation Method 2
a read head reading data from the recording layer
Data Source
AI summary
According to one embodiment, during a first write period, if determining that error correction of first user data does not exceed a limit, a determination unit causes a write processing unit to continue write processing and causes a management unit to execute second management. If determining that the error correction exceeds the limit, the determination unit causes the write processing unit to continue the write processing and causes the management unit to execute third management. During the first write period or after the first write period, the determination unit causes the management unit to execute processing of saving data belonging to a third group to a nonvolatile recording medium.