Wear-Leveling Controller Using Swap Lists for Flash Memory Blocks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory systems face challenges in maintaining stability and efficiency due to uneven erase count distribution across memory blocks, leading to performance reduction and reduced reliability.
Innovation Solution
A memory system with a controller that performs wear-leveling operations by selecting source and target memory blocks based on erase count information, swapping data to evenly distribute erase operations across memory blocks, thereby maximizing usage efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wear-leveling operations are performed to evenly distribute erase operations across memory blocks, then reliability and usage efficiency are improved, but device complexity and processing time increase
Solution Approach 1:
The memory blocks are divided into multiple groups based on their erase count characteristics. The controller selectively performs wear-leveling operations on specific groups rather than all blocks, segmenting the wear-leveling process to reduce overall complexity while maintaining reliability benefits.
Solution Approach 2:
The controller adjusts wear-leveling operation parameters dynamically based on erase count distributions. By changing operational parameters such as selecting target blocks with lowest erase counts and adjusting the scope of wear-leveling operations, the system achieves improved reliability without proportionally increasing complexity.
2Duration of action of stationary object
If wear-leveling operations are performed frequently to maintain even erase count distribution, then memory block longevity is improved, but processing time and performance reduction increase
Solution Approach 1:
The controller performs wear-leveling operations periodically based on monitored erase count distributions rather than continuously. By implementing periodic wear-leveling at strategically determined intervals, the system extends memory block lifespan while minimizing the time lost to wear-leveling operations.
Solution Approach 2:
The controller dynamically adjusts wear-leveling operation frequency and scope based on current erase count distributions and system workload conditions. By changing operational parameters adaptively, the system optimizes the balance between extending memory block lifespan and minimizing processing time losses.
3Stability of the object's composition
If comprehensive wear-leveling operations are performed across all memory blocks, then erase count distribution uniformity is improved, but system complexity and operational overhead increase
Solution Approach 1:
The controller applies wear-leveling operations locally to specific memory block groups that exhibit significant erase count variations rather than uniformly across all blocks. By targeting local areas with greatest need, the system achieves improved distribution uniformity while reducing overall operational overhead.
Solution Approach 2:
The controller modifies wear-leveling operation parameters such as target block selection criteria and operation scope based on current system state. By changing parameters adaptively, the system achieves better erase count distribution uniformity with reduced complexity compared to comprehensive uniform wear-leveling.
Data Source
AI summary
A memory system includes a memory device, having a plurality of memory blocks, for storing data and a controller for performing a wear-leveling operation between source and target memory blocks selected from the memory blocks. The controller selects the source and target memory blocks based on an erase count list storing current erase count (EC) information of the memory blocks, selects one having the greatest EC as the source memory block from the erase count list, selects the target memory block from remaining ones among the memory blocks other than both of the source memory block and an immediately previous target memory block of an immediately previous wear-leveling operation, and identifies the immediately previous target memory block of the immediately previous wear-leveling operation through a swap list including swap information of the memory blocks and information on the source and target memory blocks.