Memory Sub-System Erase Indicator for Retired Block Verification
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Solution Overview
Problem
Conventional memory sub-systems lack verification of successful data erasure during sanitize operations, particularly for retired blocks that may have failed previous erase cycles, leading to potential data recovery issues.
Innovation Solution
Implementing an erase indicator to track the success or failure of erase cycles during sanitize operations and providing a status indicator for each block, ensuring that all erase cycles are successful before marking data as fully erased.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sanitize operations are performed without verification, then the operation completes quickly, but data erasure reliability is compromised
Solution Approach 1:
The patent implements a feedback mechanism by performing verification read operations after erase cycles to confirm successful data erasure. The controller reads back data from memory blocks after erasing and verifies that the read data matches expected erased patterns, providing feedback on erasure success and enabling reliable data destruction confirmation.
2Reliability
If verification operations are added to sanitize processes, then data erasure reliability improves, but operation time increases
Solution Approach 1:
The patent applies partial verification by selecting specific memory blocks for verification read operations rather than verifying every block. The controller determines which blocks require verification based on erasure status and retirement status, performing verification only on blocks where it is most critical, thus reducing overall verification time while maintaining reliability for critical blocks.
3Object-affected harmful factors
If retired blocks are handled with standard erase procedures, then device complexity remains low, but data security is compromised
Solution Approach 1:
The patent implements local quality by applying different erase and verification procedures to different types of memory blocks. Retired blocks undergo enhanced verification compared to active blocks, with the controller performing additional read operations specifically on retired blocks to confirm complete data erasure. This targeted approach enhances security for retired blocks without unnecessarily complicating the management of all blocks.
Data Source
AI summary
Various examples are directed to memory systems comprising a component and a processing device. The memory system may comprise a plurality of blocks. A first portion of the plurality of blocks may be retired and a second portion of the plurality of blocks may be unretired. The processing device receives a sanitize operation for the plurality of blocks. The processing device initiates a first erase cycle at a first retired block of the plurality of blocks. The processing device determines that the first erase cycle was not successful and sets an erase indicator to false.