Partial Codeword Writes to Magnetic Media
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Solution Overview
Problem
Data storage devices face challenges in maintaining accurate head positioning over disk tracks, particularly when off-track conditions occur during write operations, leading to corruption of adjacent data sectors due to the need for aborting or completing writes, which can result in interference with previously written data.
Innovation Solution
Implementing a system where corrupted data sectors are partially rewritten, avoiding the need to rewrite entire codewords, and using interleaving techniques to distribute data segments across multiple sectors, along with fake writes to ensure accurate positioning and minimize adjacent track interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the write operation is aborted when an off-track condition is detected, then data integrity is maintained, but productivity decreases due to the need to re-write entire codewords
Solution Approach 1:
The patent segments the codeword into multiple data sectors distributed across different tracks. When an off-track condition is detected, only the corrupted sector is identified and re-written, rather than aborting and re-writing the entire codeword. This segmentation allows selective recovery of corrupted data while preserving intact sectors.
Solution Approach 2:
The patent applies local quality by treating each data sector independently with its own error correction coding. When corruption occurs in one sector, only that specific sector requires re-writing, while other sectors remain unaffected. This localized approach improves productivity by avoiding unnecessary re-writing of entire codewords.
2Productivity
If the write operation is completed despite off-track conditions, then productivity is maintained, but adjacent data sectors may be corrupted
Solution Approach 1:
The patent performs preliminary error detection and corruption identification during or after the write operation. By detecting which specific sectors are corrupted before finalizing the write, the system can then selectively re-write only those corrupted sectors, maintaining productivity while preventing propagation of corruption to adjacent sectors.
Solution Approach 2:
The patent implements feedback mechanisms where write operations are monitored for off-track conditions, and read operations verify data integrity. This feedback loop identifies corrupted sectors, enabling targeted re-writing operations that correct errors without causing additional adjacent track interference.
3Reliability
If entire codewords are re-written to ensure data integrity, then reliability is improved, but device complexity increases due to additional write operations
Solution Approach 1:
The patent extracts and identifies only the corrupted portions of codewords through error detection mechanisms. Instead of re-writing entire codewords, the system extracts only the specific corrupted sectors for re-writing, thereby reducing the complexity of write operation management while maintaining data integrity.
Solution Approach 2:
The patent discards the approach of re-writing entire codewords and instead recovers only the corrupted sectors through selective re-writing. This selective recovery approach reduces write operation complexity by focusing resources only on damaged data portions rather than processing entire codewords.
Data Source
AI summary
A data storage device is disclosed comprising a head actuated over a magnetic media comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors. A first codeword is encoded, and the first codeword is written to multiple data sectors of a first data track including a first data sector. A second codeword is encoded, and at least part of the second codeword to is written to the multiple data sectors of a second data track adjacent the first data track including a second data sector adjacent the first data sector of the first data track. The first codeword is partially written to at least the first data sector of the first data track when the first data sector of the first data track is corrupted by writing the second codeword to the second data track.