Hard Disk Read Channel Retry Using Selective Signal Retention

The patent divides the read signal into multiple segments and evaluates each segment independently using reliability metrics. This segmentation allows the system to identify and retain only the most reliable segments for retry operations, rather than treating the entire signal uniformly. The segmentation principle resolves the contradiction by enabling selective data retention that improves reliability without sacrificing the high-density storage capacity and spin rates.

The patent applies local quality by assigning different reliability metrics to different segments of the read signal based on their specific characteristics. Each segment is evaluated individually using metrics such as signal-to-noise ratio, and only segments meeting certain reliability thresholds are retained for retry operations. This local evaluation approach allows the system to maintain high storage density and speed while improving overall reliability by focusing resources on the most reliable data segments.

The patent performs preliminary evaluation of signal segments using reliability metrics before initiating physical re-read operations. By pre-assessing which segments are reliable and which require retry, the system avoids unnecessary physical re-reads and focuses resources only on segments that need correction. This preliminary action principle resolves the contradiction by improving error correction capability through targeted retry operations while maintaining operational efficiency by avoiding redundant reads.

The patent changes the parameter of data retention by selectively retaining only those signal segments that meet specified reliability thresholds. This parameter-based selection transforms the retry process from a blanket operation on all segments to a targeted operation on specific segments based on their reliability characteristics. The parameter changes principle resolves the contradiction by enabling efficient error correction through selective retry while maintaining high operational efficiency through reduced unnecessary operations.

The patent extracts and retains only the most reliable signal segments based on evaluated reliability metrics, discarding or marking segments that do not meet the retention criteria. This extraction principle resolves the contradiction by maintaining data completeness for reliable segments while improving storage efficiency through selective retention. The system achieves effective error management by focusing storage resources on high-quality data segments rather than retaining all segments uniformly.

The patent discards unreliable signal segments during initial read operations and recovers them through targeted retry operations only when necessary. This discarding and recovering approach resolves the contradiction by improving storage efficiency through selective retention of reliable segments while maintaining data completeness through recovery of discarded segments via retry operations. The principle enables efficient error management by recovering only the segments that actually need it.