Flash Memory Wear Leveling via Sampling Interval Segmentation

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Solution Overview

Problem

Conventional wear leveling methods for flash memory systems face challenges such as memory resource wastage, reliability issues due to data loss during power-offs, and incompatibility with new memory types, leading to uneven wear distribution and reduced system performance.

Innovation Solution

The method divides the memory life cycle into sampling intervals, independently tracking wear statistics to map heavily worn Physical Blocks to less frequently updated logical addresses, allowing for even erase/write operations without storing entire life cycle history, thus ensuring reliable wear leveling and power-off resilience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional wear leveling methods store entire life cycle history data for each Physical Block, then wear leveling accuracy is improved, but memory resource usage increases

Engineering Contradiction:
Improvewear leveling accuracyVSAvoidmemory resource usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the memory life cycle into multiple sampling intervals and only tracks wear statistics within the current sampling interval rather than storing entire life cycle history. This segmentation approach reduces memory resource usage while maintaining sufficient wear leveling accuracy through periodic sampling.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If wear leveling data is continuously updated without sampling intervals, then wear distribution evenness is improved, but reliability decreases due to power-off data loss

Engineering Contradiction:
Improvewear distribution evennessVSAvoidpower-off resilience
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent implements periodic sampling intervals for wear statistics collection instead of continuous tracking. This periodic approach ensures that wear leveling data is captured at regular intervals, maintaining wear distribution evenness while providing natural checkpoints that improve reliability against power-off data loss.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If conventional wear leveling methods track all erase/write operations continuously, then wear evenness is improved, but system complexity increases

Engineering Contradiction:
Improvewear evennessVSAvoidsystem complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies partial action by tracking wear statistics only for the current sampling interval rather than continuously monitoring all operations throughout the entire life cycle. This partial tracking approach reduces system complexity while maintaining sufficient wear evenness through periodic sampling and redistribution.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2166456B1Method and apparatus for performing wear leveling in memory
Publication Date: 2013.05.22 ACTIONS SEMICONDUCTOR CO LTD
  • EP2166456B1 patent drawingFigure 1
  • EP2166456B1 patent drawingFigure 2
  • EP2166456B1 patent drawingFigure 3

AI summary

The embodiment of the solution provides a method for performing wear leveling in a memory. The method includes: dividing the lifecycle of the memory which includes more than one physical blocks into at least one sampling interval; for each sampling interval, getting the first physical block by taking statistics of the degree of the wear leveling of each physical block in the memory in the current sampling interval; getting the second physical block by taking statistics of the updating times of each logical address in the current sampling interval; exchanging the logical addresses and data of the first physical block and the second physical block. The embodiment of the solution also provides an apparatus corresponding the method.