Shingled Magnetic Recording Band Binding via Late Defect Adaptation

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Solution Overview

Problem

Shingled magnetic recording (SMR) data storage devices face challenges in efficiently managing defective sectors, leading to suboptimal performance and capacity utilization due to early binding of band boundaries without considering actual defect locations, resulting in inefficient use of disc space and increased read-modify-write times.

Innovation Solution

Implementing a late binding method that defines band boundaries after error discovery, using guard tracks and flexible band sizes to accommodate defective sectors, allowing for dynamic reconfiguration of band layouts to ensure minimum usable capacity and efficient data storage without premature disc retirement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If band boundaries are defined early without considering defect locations, then the binding process is simple and fast, but disc space is wasted and capacity utilization is reduced

Engineering Contradiction:

Improvebinding process simplicityVSAvoidusable disc capacity

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent implements dynamic band boundary definition where bands are formed after defect detection. The binding process adapts to actual defect locations, allowing flexible adjustment of band boundaries to exclude defective sectors while maximizing usable capacity. This dynamic approach transforms the static early binding process into a adaptive post-detection process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary defect detection and mapping before finalizing band boundaries. By identifying defective sectors in advance through error discovery scans, the system can pre-plan optimal band configurations that avoid these defects, ensuring maximum capacity utilization from the outset rather than wasting space on potentially defective areas.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If band boundaries are fixed without defect information, then the structure is stable and simple, but read-modify-write times increase due to inefficient band selection

Engineering Contradiction:

Improveband structure stabilityVSAvoidread-modify-write time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent incorporates feedback from error discovery scans into the band binding process. Defect detection results feed back to adjust band boundary definitions, creating an iterative process where band structures are optimized based on actual disc conditions. This feedback mechanism enables the system to identify and isolate defective areas, reducing unnecessary read-modify-write operations on problematic sectors.

Inventive Principle:

Principle #23Feedback

3Device complexity

If guard tracks are not used, then the band layout is simple, but defective sectors cannot be accommodated and may cause data loss

Engineering Contradiction:

Improveband layout complexityVSAvoiddata integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces guard tracks as intermediary elements between data tracks and defective sectors. These guard tracks act as buffers that isolate defective areas from usable data regions, preventing defect propagation while maintaining data integrity. The guard tracks serve as mediators that protect valid data from the harmful effects of defective sectors without requiring complex redesign of the entire band structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If early binding is used, then the process is efficient and fast, but disc space is over-provisioned and wasted

Engineering Contradiction:

Improvebinding process efficiencyVSAvoidusable storage capacity

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent changes the timing parameter of band boundary definition from pre-definitive (early binding) to post-detection (late binding). By deferring the binding process until after defect detection, the system can accurately calculate and optimize usable capacity based on actual disc conditions, eliminating over-provisioning and wasting space on defective areas that would be excluded from usable capacity calculations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9460751B2Binding shingled recording bands

Publication Date: 2016.10.04 SEAGATE TECH LLC

AI summary

Systems and methods are disclosed for binding shingled recording bands in data storage devices, particularly devices employing shingled magnetic recording. In one embodiment, an apparatus may comprise a controller configured to define boundaries of an area of a data storage medium based on a constraint and a list of defective sectors. In another embodiment, an apparatus may comprise a data storage device including a memory configured to store data in a shingled manner where one track partially overlaps an adjacent track, and a controller configured to define boundaries of a plurality of bands, each band including a plurality of tracks of the memory, based on the results of an error discovery scan for defective sectors of the memory.