Heal Leveling for Nonvolatile Memory Endurance
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Solution Overview
Problem
Nonvolatile memory devices face endurance limitations due to access cycle constraints, where different memory blocks reach endurance limits at different times, and existing wear leveling and healing technologies have limitations in extending memory life without excessive overhead.
Innovation Solution
Heal leveling technology distributes healing cycles among memory blocks to improve endurance and extend lifetime by moving dormant data to blocks with high healing cycles, minimizing the variation in healing counts and access patterns, thereby reducing the need for frequent healing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal cycling healing operations are applied to repair damaged memory cells, then memory cell reliability is improved, but the number of times the healing process can be applied is limited and overhead increases
Solution Approach 1:
The patent applies preliminary action by proactively moving data from blocks that have undergone a certain number of healing operations to blocks with fewer healing operations, before the blocks reach their endurance limits. This preventive approach reduces the need for frequent healing operations and extends memory device lifetime without excessive overhead.
Solution Approach 2:
The patent implements a dynamic data redistribution mechanism that continuously monitors healing operation counts across different memory blocks and adaptsively moves data based on current block conditions. This dynamic approach optimizes the distribution of healing operations and prevents any single block from being over-healed.
2Duration of action of stationary object
If wear leveling is applied to distribute access cycles evenly across memory blocks, then memory endurance is improved, but access performance may be degraded due to data movement overhead
Solution Approach 1:
The patent applies local quality by treating different memory blocks differently based on their specific healing operation counts and wear levels. Instead of uniform data distribution, the system selectively moves data from blocks with high healing counts to blocks with low healing counts, optimizing both endurance and performance by minimizing unnecessary data movements.
3Duration of action of stationary object
If healing operations are frequently applied to extend memory block lifetime, then effective lifetime is improved, but the variation in healing counts among blocks increases and overhead increases
Solution Approach 1:
The system performs preliminary data migration from blocks that have reached a threshold number of healing operations to blocks with fewer operations, preventing excessive healing count variation and extending effective lifetime before blocks fail.
Solution Approach 2:
The patent implements a feedback mechanism that monitors healing operation counts across memory blocks and triggers data redistribution when certain thresholds are reached. This feedback-driven approach maintains balanced healing counts and optimizes memory device lifetime.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Heal leveling enhances memory access performance and extends the effective lifetime of memory blocks by evenly distributing healing cycles, reducing the likelihood of further healing needs and minimizing overhead compared to traditional wear leveling methods.
Implementation Method 1
thermal cycling can be used to repair, or heal, damaged memory cells
Data Source
AI summary
Technology is described that increases endurance of memory devices through heal leveling. Heal leveling is a lightweight solution to distribute healing cycles among memory blocks. Approaches described herein can accomplish heal leveling without introducing a large amount of overhead. Heal leveling significantly improves the access performance and the effective lifetime of memory blocks. By more evenly distributing the heal count it may not be necessary to directly apply wear leveling based on access counts of each block because each block will be more evenly accessed in the long run. Heal leveling may be performed by moving data that is seldom or never modified after creation, such as read-only files, to blocks having suffered the greatest number, or a high number, of healing cycles.