Memory System Bad Block Detection via Test Read
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Solution Overview
Problem
Existing memory systems face challenges in efficiently detecting and managing bad memory blocks, particularly when read counts are unknown due to sudden power-offs, leading to difficulties in performing targeted read reclaim operations.
Innovation Solution
A memory system with a bad memory block detection unit that utilizes a test read management unit and test read operation unit to generate and update a test read table, performing test read operations on memory blocks to identify and manage bad blocks, thereby enabling effective read reclaim operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If test read operations are performed on all memory blocks to detect bad blocks, then detection precision is improved, but device complexity and operation time increase
Solution Approach 1:
The memory blocks are divided into multiple groups, and test read operations are performed selectively on specific groups rather than all blocks. This segmentation approach maintains detection precision for critical blocks while reducing overall system complexity and operation time.
Solution Approach 2:
Instead of performing test read operations on all memory blocks, the system performs partial testing on selected blocks based on usage patterns and risk assessment. This partial action approach achieves sufficient detection precision for problematic blocks while avoiding the complexity and time cost of comprehensive testing.
2Reliability
If test read operations are performed frequently to detect bad blocks, then reliability is improved, but productivity decreases
Solution Approach 1:
Test read operations are performed periodically at predetermined intervals rather than continuously or frequently. This periodic approach maintains memory system reliability by detecting bad blocks at appropriate intervals while minimizing interference with normal data access operations and maintaining productivity.
Solution Approach 2:
The system performs preliminary detection of bad blocks during idle periods or background operations before they affect normal productivity. This preliminary action ensures reliability is maintained while minimizing impact on data access speed during active operations.
3Productivity
If read reclaim operations are delayed until bad blocks are detected, then memory system efficiency is maintained, but loss of information increases
Solution Approach 1:
The system continuously monitors memory block status through test read operations and provides feedback to trigger read reclaim operations when bad blocks are detected. This feedback mechanism ensures that data is recovered from bad blocks promptly, preventing information loss while maintaining overall memory system efficiency through targeted reclaim operations.
Data Source
AI summary
A memory system includes: a memory device including a plurality of memory blocks; a bad memory block detection unit suitable for performing a test read operation on the plurality of memory blocks to detect a bad memory block; and a controller suitable for controlling the memory device to perform a read reclaim operation to the bad memory block according to a result of detecting the bad memory block by the bad memory block detection unit.