Multi-Sector Codeword Segmentation for Disk Write Reliability
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Solution Overview
Problem
Data storage devices face challenges in maintaining accurate head positioning and error correction during write operations due to off-track conditions and other disturbances, which can lead to incomplete or corrupted data storage.
Innovation Solution
The implementation of a control circuitry that encodes write data into codewords spanning multiple data sectors, using error correction codes like LDPC or Reed-Solomon codes, and employing interleaving to improve correction power, along with real-time on-the-fly encoding and retry mechanisms to handle off-track conditions by regenerating codewords during each disk revolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is written to multiple sectors during off-track conditions, then data integrity is improved, but device complexity increases
Solution Approach 1:
The codeword is divided into multiple segments that can be written to different sectors across multiple disk revolutions. The control circuitry processes and writes portions of the codeword in a segmented manner, allowing data to be distributed across multiple sectors while maintaining manageable control logic complexity
Solution Approach 2:
The system uses periodic disk revolutions to write different segments of the codeword to different sectors. Each revolution provides an opportunity to write additional segments, creating a periodic writing pattern that improves data integrity without requiring continuous complex control operations
2Reliability
If codeword is written over multiple disk revolutions, then error correction capability is improved, but writing speed decreases
Solution Approach 1:
The system performs preliminary encoding of the entire codeword before writing begins. This preliminary action allows the encoded data to be prepared in advance and written systematically across multiple revolutions, improving error correction capability while maintaining efficient writing throughput through batch processing
Solution Approach 2:
The writing operation continues across multiple disk revolutions without interruption, maintaining continuous useful action. The control circuitry systematically writes different segments of the codeword in each revolution, ensuring that the writing process remains productive throughout the extended operation
Data Source
AI summary
A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data sectors. During a first revolution of the disk, write data is first encoded into a codeword spanning at least a first data sector and a second data sector and a first part of the codeword is written to the first data sector. During a second revolution of the disk, the write data is second encoded into the codeword and a second part of the codeword is written to the second data sector.