Interleaver Patterns for Inter-Track Interference in Storage
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Solution Overview
Problem
As areal densities for magnetic data storage increase, inter-track interference becomes a significant challenge in distinguishing data on adjacent tracks, as existing techniques fail to effectively minimize interference, particularly when interleaving logical sectors across physical sectors on disk drives.
Innovation Solution
The method involves defining and selecting different interleaver patterns for adjacent tracks to distribute logical data sectors across physical sectors, ensuring that each segment of a logical sector on one track is adjacent to segments of different logical sectors on adjacent tracks, thereby reducing inter-track interference by using sector and segment interleaving patterns that avoid simultaneous use of the same pattern on adjacent tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same interleaver pattern is used on adjacent tracks, then the writing process is simplified, but inter-track interference increases making data distinction difficult
Solution Approach 1:
The patent applies different interleaver patterns to different tracks, making each track have a unique local characteristic. Specifically, adjacent tracks use interleaver patterns that are cyclic shifts of each other, creating local differentiation that minimizes inter-track interference while maintaining overall system coherence through the structured relationship between patterns.
Solution Approach 2:
The patent changes the interleaver pattern parameter across adjacent tracks by using cyclic shifts. Instead of using the same pattern, each track uses a pattern that is a cyclic shift of the previous track's pattern, thereby changing the parameter to reduce interference while maintaining the fundamental interleaving structure.
2Quantity of substance
If areal density is increased to improve storage capacity, then more data can be stored, but inter-track interference increases making reading more difficult
Solution Approach 1:
By differentiating the interleaver patterns on adjacent tracks through cyclic shifts, the patent creates local quality differences that allow read heads to distinguish between tracks even when track spacing is reduced for higher areal density. This local differentiation prevents the harmful effect of inter-track interference that would otherwise limit storage capacity increases.
3Quantity of substance
If read head dimensions are reduced to achieve higher areal density, then storage capacity increases, but the ability to distinguish data on adjacent tracks deteriorates
Solution Approach 1:
The patent changes the interleaver pattern parameter across adjacent tracks using cyclic shifts, which creates distinct data patterns that can be distinguished even by smaller read heads. This parameter change ensures that each track has a unique pattern signature, allowing precise data distinction despite reduced read head dimensions and higher areal density.
Data Source
AI summary
A method for storing data in groups of logical data sectors across a plurality of contiguous data tracks of a data storage medium includes defining a plurality of interleaver patterns, each interleaver pattern including a sector interleaving pattern specifying a respective order in which segments of respective ones of the logical data sectors are spread across physical data sectors of a respective one of the contiguous data tracks. For each respective group of logical data sectors, a respective interleaver pattern is selected. Data is written from each group of logical data sectors to one of the data tracks using the selected interleaver pattern. Each respective group of logical data sectors is written to its respective data track using a different interleaver pattern from any other group of logical data sectors written to an adjacent data track, so that no two adjacent data tracks are written using the same interleaver pattern.