Memory Controller Wear-Leveling via Page Grouping and Interleaving
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Solution Overview
Problem
Nonvolatile memory devices, such as RRAM and PCRAM, have limited write endurance due to concentrated write operations on specific memory cell regions, leading to reduced device lifetime, which existing wear-leveling techniques struggle to address effectively in multi-memory systems.
Innovation Solution
A memory system with a memory controller that performs parallel wear-leveling operations across multiple memory banks by grouping pages and mapping logical addresses to physical addresses, ensuring even distribution of write operations through an interleaving scheme, thereby extending the write endurance of memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If write operations are concentrated on a specific memory cell region, then write speed is improved, but write endurance is reduced
Solution Approach 1:
The memory device is divided into multiple memory blocks, and the wear-leveling module segments write operations to distribute them across different blocks. By calculating overwrite counts for each block and selecting target blocks with lower counts, the system segments the write workload to prevent concentration on specific regions, thereby maintaining write speed while improving write endurance.
2Reliability
If wear-leveling operations are performed sequentially, then write endurance is improved, but processing speed is reduced
Solution Approach 1:
The wear-leveling module performs wear-leveling operations periodically based on overwrite counts rather than continuously or sequentially. By monitoring overwrite counts and triggering wear-leveling only when thresholds are met, the system achieves periodic action that maintains write endurance while minimizing interference with normal write operations, thus preserving processing speed.
Solution Approach 2:
The system calculates and monitors overwrite counts in advance for each memory block before performing wear-leveling operations. This preliminary calculation allows the wear-leveling module to proactively identify suitable target blocks, enabling efficient wear-leveling execution without requiring sequential scanning or trial-and-error approaches, thereby improving processing speed.
3Manufacturing precision
If mapping between logical and physical addresses is complex, then wear-leveling precision is improved, but device complexity increases
Solution Approach 1:
The wear-leveling module implements a feedback mechanism by continuously monitoring overwrite counts of memory blocks and using this information to dynamically adjust mapping decisions. The system calculates overwrite counts based on previous write operations and uses this feedback to select target blocks with lower counts, achieving precise wear-leveling through data-driven decisions rather than complex predetermined mapping schemes.
Solution Approach 2:
The system changes the parameter used for mapping from fixed logical-to-physical address correspondence to dynamic selection based on overwrite count thresholds. By adjusting the selection criterion from static addressing to dynamic parameter-based selection (overwrite count), the system achieves higher wear-leveling precision while using a relatively simple counting and comparison mechanism rather than complex mapping algorithms.
Data Source
AI summary
A memory system may include a memory device comprising a plurality of memory banks, and a memory controller suitable for allocating data of successive logical addresses to the respective memory banks, and controlling read/write operations of the data, wherein the memory controller groups pages of the respective memory banks, and performs a wear-leveling operation based on the read/write operations of the data on each group of the pages.