Nonvolatile Memory Management for Abnormal Power-Off Recovery
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Solution Overview
Problem
Conventional nonvolatile memory management methods require numerous erase and re-program operations to ensure data accuracy after abnormal power-offs, leading to extended reboot times and reduced memory cell lifespan.
Innovation Solution
A method that determines whether a nonvolatile memory was normally or abnormally powered off, searching for erroneous pages and programming dummy data in them before resuming normal operations, thereby avoiding invalid data retrieval and reducing the need for excessive erase operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional management methods are used to ensure data accuracy after abnormal power-off, then data accuracy is improved, but reboot time is extended and memory cell lifespan is reduced
Solution Approach 1:
The system performs preliminary actions by detecting the power-off state (normal or abnormal) and metadata status before attempting data retrieval. This preliminary detection prevents unnecessary erase operations and guides the system to execute only the necessary correction actions, thereby reducing reboot time while maintaining data accuracy.
Solution Approach 2:
The system implements feedback mechanisms by checking metadata validity and power-off state, then adjusting the data recovery process accordingly. This feedback loop allows the system to identify erroneous pages and perform targeted corrections without executing unnecessary full memory erases, thus reducing time loss while ensuring data accuracy.
2Reliability
If conventional management methods are used to ensure data accuracy after abnormal power-off, then data accuracy is improved, but the number of erase operations increases
Solution Approach 1:
The system performs preliminary detection of power-off state and metadata status before executing erase operations. This preliminary action identifies which pages contain erroneous data and allows the system to perform targeted erases only where necessary, significantly reducing the total number of erase operations while maintaining data accuracy.
Solution Approach 2:
Instead of performing uniform erase operations across the entire memory, the system applies local quality by identifying and erasing only specific erroneous pages where data corruption occurred. This localized approach reduces the quantity of erase operations while ensuring data accuracy in affected areas.
3Reliability
If numerous erase and re-program operations are performed, then data accuracy is improved, but memory cell lifespan is reduced
Solution Approach 1:
The system performs preliminary detection of erroneous pages before executing erase operations. This preliminary action enables targeted correction of only the affected pages, reducing the total number of erase-reprogram cycles and thereby extending memory cell lifespan while maintaining data accuracy.
Solution Approach 2:
The system applies local quality by performing erase operations only on specific erroneous pages rather than the entire memory array. This localized approach minimizes the number of cycles each memory cell undergoes, extending overall memory cell lifespan while ensuring data accuracy in corrupted areas.
Data Source
AI summary
A management method for a memory system executes a first memory system management sequence upon determining that the memory system was normally powered off, and a second sequence upon determining that the memory system was abnormally powered off. The first sequence allows immediate execution of a program operation at a valid data page location extracted from stored metadata, while the second sequence allows execution of a program operation only after programming dummy data to at least one erroneous page.