NAND Memory Bad Block Management via Segmented Control
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Solution Overview
Problem
Existing bad block management methods for NAND memory in portable terminals face collisions between file system-based and external BBM, leading to inefficient management and potential access conflicts, especially when dealing with bad blocks in information management tables and user data.
Innovation Solution
A dual approach to bad block management is implemented, where one method manages bad blocks within the non-volatile memory's information management table and another within the file system, using a combination of write remapping and write mapping to allocate and replace bad blocks, thereby avoiding collisions and optimizing memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bad block management method is used for both information management tables and user data, then the management process is simplified, but collisions and access conflicts occur between file system-based BBM and external BBM
Solution Approach 1:
The patent segments the non-volatile memory into distinct areas: a first area for information management tables and a second area for user data. Different bad block management methods are applied to each area - the file system-based BBM manages bad blocks in the second area, while an external BBM manages bad blocks in the first area. This segmentation prevents collisions between the two management methods by isolating their respective management scopes to specific memory areas.
2Ease of operation
If the file system performs its own BBM, then user data management is improved, but collisions occur with external BBM for information management tables
Solution Approach 1:
The patent applies different management qualities to different parts of the memory system. The file system-based BBM is applied locally to the second area (user data) where it excels at managing user data efficiently. The external BBM is applied locally to the first area (information management tables) where it provides specialized management. This local quality approach allows each BBM method to operate optimally in its designated area without interfering with the other.
3Adaptability or versatility
If a wide range of non-volatile memory is covered by external BBM, then memory management coverage is improved, but conflicts arise with file system BBM
Solution Approach 1:
The patent divides the non-volatile memory into distinct segments with different management responsibilities. The first area (information management tables) is managed exclusively by the external BBM, while the second area (user data) is managed by the file system BBM. This segmentation allows the external BBM to cover a wide range of memory areas without causing conflicts, as each area has a designated manager that operates independently within its scope.
Data Source
AI summary
A terminal apparatus including a non-volatile memory for which writing is performed in units of blocks; and a control unit configured to perform a first method of managing bad blocks in the non-volatile memory with respect to blocks corresponding to an information management table in a file system of the non-volatile memory, and to perform a second method of managing bad blocks in the non-volatile memory with respect to blocks corresponding to user data in the file system.