Defect Scanning Using Syndrome Convergence for Precise Sector Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional defect detection methods in disk drive manufacturing often result in unnecessary mapping out of entire sectors due to the identification of media defects, leading to wastage of usable storage area, as they fail to accurately differentiate between defective and marginal sectors.
Innovation Solution
The implementation of a data processing system with a data decoder circuit and sector defect indication circuit that uses a periodic pattern to identify defective regions by converging with a non-zero syndrome value, allowing for more precise defect mapping and minimizing wastage by adjusting the number of global and local iterations based on defect percentage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional wedge read defect detection is used, then defect detection is performed, but entire sectors are unnecessarily mapped out as defective, wasting usable storage area
Solution Approach 1:
The patent segments the storage medium into smaller analysis units within sectors. Instead of treating entire sectors as defective based on wedge read results, the system divides sectors into multiple regions and evaluates each region independently using iterative decoding, allowing only truly defective portions to be mapped out while preserving usable areas.
Solution Approach 2:
The patent changes the detection parameter from simple amplitude threshold comparison in wedge reads to iterative syndrome value convergence analysis. By using multiple decoding iterations and analyzing syndrome value patterns, the system can distinguish between marginal sectors that can still be used and truly defective sectors, preventing unnecessary mapping.
2Measurement precision
If iterative decoding with syndrome value convergence is used, then precise defect identification is achieved, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary actions by first conducting a standard wedge read to identify potential defect locations, then selectively applying iterative decoding only to sectors containing identified defects. This two-stage approach filters out clearly usable sectors early, limiting the computationally intensive iterative process to only those sectors needing detailed analysis.
Solution Approach 2:
The patent applies partial action by performing a limited number of decoding iterations (e.g., 3-7 iterations) rather than exhaustive decoding. This partial iteration approach provides sufficient precision for defect identification while avoiding the excessive processing time that would result from continuing iterations until complete convergence or maximum iteration limits.
Data Source
AI summary
The present invention is related to systems and methods for defect scanning.