Magnetic Disk Selective Sector Refresh for Data Quality
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Solution Overview
Problem
Magnetic disk devices face challenges in managing quality-degraded recording sectors, which affect data integrity and device performance, particularly in hybrid recording systems that combine shingled and conventional magnetic recording methods.
Innovation Solution
A magnetic disk device with a determination unit to identify quality-degraded recording sectors and a refresh processing unit to read and rewrite target sectors, ensuring data quality by refreshing sectors in bands with degraded quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If shingled magnetic recording is used to increase storage capacity, then the recording density is improved, but the data quality degrades over time due to write head wear and magnetic interference
Solution Approach 1:
The system performs preliminary detection of quality-degraded recording sectors and proactively refreshes them before complete data degradation occurs. The determination unit identifies sectors with deteriorating quality, and the refresh processing unit rewrites data to these sectors in advance, preventing data loss before it happens.
Solution Approach 2:
The system implements a feedback mechanism where the determination unit continuously monitors recording sector quality and provides information to the refresh processing unit. Based on this feedback about degraded sectors, the system selectively refreshes only the necessary sectors, creating a closed-loop quality maintenance system.
2Reliability
If all recording sectors are refreshed to maintain data quality, then data integrity is improved, but the write head lifespan is reduced due to increased wear
Solution Approach 1:
Instead of uniformly refreshing all recording sectors, the system applies local quality management by selectively refreshing only the quality-degraded recording sectors identified by the determination unit. This localized approach maintains data integrity where needed while avoiding unnecessary wear on the write head in sectors that still have good quality.
Solution Approach 2:
The system performs partial action by refreshing only the necessary portion of recording sectors (those with degraded quality) rather than all sectors. This partial refreshing approach is sufficient to maintain overall data integrity while significantly reducing the total wear on the write head compared to complete sector refreshing.
3Duration of action of stationary object
If quality-degraded sectors are detected and refreshed selectively, then write head wear is reduced, but the complexity of the control system increases
Solution Approach 1:
The control system is segmented into distinct functional units: a determination unit for detecting quality-degraded sectors and a refresh processing unit for rewriting data. This segmentation allows each unit to perform its specific function efficiently, managing complexity through modular design while achieving selective sector refreshing.
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 extends the lifespan of the write head by selectively refreshing quality-degraded sectors, maintaining data quality and device performance.
Implementation Method 1
a write head writing data to the disk
Implementation Method 2
a read head reading data from the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk, a write head, a write processing unit selecting a shingled magnetic recording, a determination unit, and a refresh processing unit. The determination unit determines whether a quality-degraded recording sector exists in all recording sectors in each of the bands. If it is determined that a target band including the quality-degraded recording sector exists in the bands, the refresh processing unit refreshes target recording sectors. The target recording sectors include the quality-degraded recording sector. In the target band, the number of the target recording sectors is less than the number of all recording sectors.