Magnetic Disk Write Control for Predicted Error Correction Limits
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Solution Overview
Problem
Magnetic disk devices face challenges in efficiently managing track-by-track error correction and head positioning during data write operations, particularly in hybrid recording-type devices that switch between conventional and shingled magnetic recording, leading to inefficiencies and potential data loss.
Innovation Solution
A magnetic disk device with a correction limit prediction unit that calculates an excess amount of write head protrusion and predicts whether error correction will reach its limit, allowing for informed decision-making on continuing write processing, thereby enhancing data integrity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If shingled magnetic recording is used to increase storage capacity, then recording density is improved, but track positioning precision deteriorates due to head protrusion affecting adjacent tracks
Solution Approach 1:
The system performs preliminary error assessment during the write operation by calculating excess amounts and predicting error correction limits before actually exceeding them. This allows the system to take preventive action (ending write processing) before data integrity is compromised, resolving the contradiction between maintaining high recording density and ensuring track positioning precision.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors head positioning, calculates excess amounts, assesses error rates, and adjusts write processing accordingly. This closed-loop control allows the system to maintain high storage capacity utilization while dynamically preventing positioning errors on adjacent tracks through real-time feedback and corrective action.
2Productivity
If write processing continues to maximize productivity, then data write speed is improved, but data integrity deteriorates when error correction limits are exceeded
Solution Approach 1:
The system performs preliminary error assessment and prediction during write operations, calculating excess amounts and predicting when error correction limits will be reached. By taking preliminary action to end write processing before limits are exceeded, the system prevents data integrity loss while maximizing productive write operations up to the safe limit.
Solution Approach 2:
The patent implements continuous feedback monitoring of error rates and correction limits during write processing. The system adjusts write operations in real-time based on feedback from error assessment, allowing maximum productivity within safe operational boundaries while preventing data integrity deterioration through dynamic control.
3Reliability
If track-by-track error correction is implemented to improve data reliability, then data integrity is improved, but device complexity increases
Solution Approach 1:
The patent extracts and addresses only the critical portions of error correction needs by implementing targeted track-by-track correction for affected tracks while leaving unaffected tracks unchanged. This selective approach maintains data integrity where needed without applying complex correction procedures universally, thereby reducing overall device complexity while preserving reliability.
Solution Approach 2:
The system applies error correction locally only to tracks that are actually affected by head protrusion issues, rather than uniformly to all tracks. This localized quality approach ensures data integrity for problematic tracks while avoiding unnecessary complexity in tracks that don't require correction, optimizing the balance between reliability and device complexity.
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
The solution improves data integrity by preventing write processing from exceeding error correction limits, reducing data loss and enhancing the reliability of hybrid recording-type devices.
Implementation Method 1
conventional magnetic recording (CMR) type that writes multiple tracks at intervals in a radial direction of a disk
Implementation Method 2
shingled magnetic recording (SMR) type magnetic disk devices that overwrite multiple tracks in the radial direction of the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a first disk having a first data track and a second data track, a first write head, a write processing unit, an error correction unit, a correction limit prediction unit, and a determination unit. During a write period, the correction limit prediction unit calculates an excess amount, calculates a metric value by multiplying a first weight coefficient by the excess amount, updates a cumulative metric value, and generates first prediction information. The determination unit determines whether or not to allow the write processing unit to continue write processing for the second data track based on the first prediction information.