Flash Memory Wear Leveling via Erased Sequence Tracking
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Solution Overview
Problem
Conventional wear leveling methods for flash memory fail to effectively distribute the wear of memory blocks, leading to premature deterioration and reduced lifespan of flash drives, as they often incorrectly identify blocks for exchange, thereby accelerating wear and wasting usable storage capacity.
Innovation Solution
A wear leveling method that divides non-volatile memory into data and spare areas, using a memory management module to select physical blocks based on erased sequences and exchange them to balance utilization, employing a table to record utilization information and perform logical block mappings to evenly distribute wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wear leveling methods sequentially exchange blocks between data area and spare area, then block utilization is attempted to be balanced, but the exchanged blocks may not be those with lesser erase times, causing accelerated wear and limited effectiveness
Solution Approach 1:
The patent applies preliminary action by pre-recording the erased sequences of all blocks in the spare area before performing wear leveling exchange. This allows the system to identify and select blocks with the least erase times in advance, ensuring that only appropriate blocks are exchanged with data area blocks, thereby preventing accelerated wear and improving wear leveling effectiveness.
Solution Approach 2:
The patent implements feedback by maintaining a record of erase sequences for each block and using this information to guide the block exchange process. The system continuously monitors and updates the erased sequence information, and this feedback is used to make informed decisions about which blocks to exchange, ensuring optimal wear distribution over time.
2Reliability
If blocks are frequently exchanged to balance wear, then wear distribution is improved, but the performance of the entire flash memory is reduced when good blocks cannot provide enough space for storing data
Solution Approach 1:
The patent uses feedback by continuously tracking the erased sequence and wear status of each block. This information is used to make intelligent decisions about when and which blocks to exchange, ensuring that wear leveling is performed only when beneficial, thereby maintaining both uniform wear distribution and adequate available storage capacity.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the block exchange criteria based on the recorded erased sequences. Instead of fixed or arbitrary exchange rules, the system modifies its behavior based on the actual wear parameters of each block, optimizing the balance between wear distribution and available storage capacity.
3Device complexity
If sequential block exchange is performed without tracking erase times, then the process is simple, but the exchanged blocks may be those with greater erase times, accelerating wear
Solution Approach 1:
The patent applies preliminary action by pre-recording and tracking the erased sequences of all blocks before the wear leveling exchange process. This preliminary tracking adds minimal complexity but ensures that blocks with the least erase times are correctly identified and selected for exchange, preventing accelerated wear of already-worn blocks.
Solution Approach 2:
The patent implements feedback by using the recorded erase sequence information to guide block exchange decisions. This feedback mechanism provides a simple yet effective way to track block wear status and make informed exchange decisions, improving reliability without significantly increasing system complexity.
Data Source
AI summary
A wear leveling method for non-volatile memory is provided, by which the non-volatile memory is substantially divided into a plurality of blocks and the blocks are grouped into a data area and a spare area. The method includes selecting a block based on an erased sequence when getting the block from the spare area. The method also includes performing a wear leveling procedure.