Wear Leveling for Non-Volatile Memory Using Dual-Parameter Selection
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Solution Overview
Problem
Conventional wear leveling methods in rewritable non-volatile memory modules fail to evenly distribute the usage of physical erasing units, leading to uneven wear and reduced lifespan, as units with lower operation values are frequently switched to spare areas, while those with higher operation values are more likely to be re-associated with data areas and further stressed.
Innovation Solution
A wear leveling method that records operation and usage situation values of physical erasing units, selecting units with lower operation values and higher usage situation values to copy data, thereby reducing the likelihood of these units being re-associated with the data area and promoting more even usage across all units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional wear leveling switches physical erasing units with lower operation values to spare areas, then the lifespan of the memory module is extended, but physical erasing units with higher operation values are repeatedly re-associated with data areas and subjected to excessive stress
Solution Approach 1:
The patent introduces a usage situation value parameter in addition to the operation value parameter. This dual-parameter system changes the selection criteria from single-factor (operation value only) to multi-factor (operation value and usage situation value), enabling more balanced wear distribution across physical erasing units.
Solution Approach 2:
The patent implements a feedback mechanism where the memory management circuit continuously monitors both operation values and usage situation values of physical erasing units, and dynamically adjusts the selection of units for wear leveling operations based on this monitored data, creating a closed-loop control system.
2Device complexity
If physical erasing units are switched based solely on operation values, then the selection process is simple, but the wear leveling effect is insufficient and units with higher operation values are repeatedly stressed
Solution Approach 1:
The patent adds a new parameter (usage situation value) to the existing parameter (operation value), transforming the selection criterion from single-dimensional to two-dimensional. This parameter expansion enables more sophisticated wear leveling while maintaining computational efficiency.
Solution Approach 2:
The patent transitions from one-dimensional wear leveling (based only on operation counts) to two-dimensional wear leveling by introducing the usage situation value dimension, which reflects the recency and frequency of unit usage patterns.
Data Source
AI summary
A wear leveling method for a rewritable non-volatile memory module, a memory control circuit unit, and a memory storage apparatus are provided. The rewritable non-volatile memory module includes a plurality of physical erasing units. The method includes: recording an operation value of each of the physical erasing units; recording a usage situation value of each of the physical erasing units; and selecting a first physical erasing unit and a second physical erasing unit from the physical erasing units according to the operation values of the physical erasing units and the usage situation values of the physical erasing units and copying valid data stored in the first physical erasing unit to the second physical erasing unit.