Flash Memory Block Retirement Using ECC Error History
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Solution Overview
Problem
Flash memory devices experience data corruption due to mechanisms like program disturb, read disturb, and erase disturb, leading to uncorrectable ECC errors, which result in reduced system performance and potential failure, necessitating the retirement of blocks, thereby reducing memory capacity and increasing wear on remaining blocks.
Innovation Solution
Implementing a system that performs read operations on memory cells and uses an indicator to determine whether to retire defective groups of memory cells based on previous uncorrectable error status, thereby managing block retirement efficiently and maintaining system capacity while limiting wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocks are retired when uncorrectable ECC errors occur, then data reliability is improved, but memory capacity is reduced and wear on remaining blocks increases
Solution Approach 1:
The patent applies preliminary action by performing a read operation and error checking on a block before retiring it. The system reads the block, checks for uncorrectable ECC errors, and only retires the block if errors are detected. This preliminary verification ensures that reliable blocks are not prematurely retired, thereby maintaining memory capacity while ensuring data reliability.
Solution Approach 2:
The patent implements feedback by using the result of the read operation and ECC error check to determine whether to retire the block. The system continuously monitors block health through read operations and uses the error detection feedback to make informed retirement decisions, optimizing the balance between reliability and capacity.
2Reliability
If blocks are retired when uncorrectable ECC errors occur, then data reliability is improved, but wear on remaining blocks increases
Solution Approach 1:
The patent performs a preliminary read operation and error check before retiring a block. This preliminary action ensures that only blocks with actual uncorrectable errors are retired, preventing premature retirement of healthy blocks and thereby extending the overall lifetime of the memory device while maintaining data reliability.
Solution Approach 2:
The system uses feedback from read operations and ECC error checks to make intelligent retirement decisions. By continuously monitoring block health and using this feedback to guide retirement decisions, the system optimizes the balance between maintaining data reliability and extending the operational lifetime of the memory device.
Data Source
AI summary
The present disclosure includes methods, devices, and systems for error detection/correction based memory management. One embodiment includes performing a read operation with respect to a particular group of memory cells of a memory device and, if the read operation results in an uncorrectable error, determining whether to retire the particular group of memory cells in response to a status of an indicator corresponding to the particular group of memory cells, wherein the status of the indicator indicates whether the particular group of memory cells has a previous uncorrectable error associated therewith.