Memory Controller Copy Block Management for Read Disturbance
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Solution Overview
Problem
Existing memory systems face challenges in adjusting capacity and ensuring data reliability while minimizing management costs and read disturbance, particularly in portable electronic devices where data integrity and storage efficiency are critical.
Innovation Solution
A memory system with a controller that generates copy blocks for user data, storing map data including logical and physical addresses, and alternates access between original and copy data to prevent read disturbance, thus maintaining data reliability and capacity according to host selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copy blocks are generated to ensure data reliability, then data reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements data reliability by creating copy blocks that contain duplicate data of original blocks. When the original block becomes closed, the controller generates a copy block by copying data from the original block to a free block with the same page address. This copying mechanism ensures data redundancy and reliability while managing the complexity through systematic block management and mapping structures.
2Adaptability or versatility
If map data structure is expanded to include copy block information, then data management capability is improved, but memory overhead increases
Solution Approach 1:
The patent segments the map data structure into distinct fields: logical address, original block address, copy block address, and common page address. This segmentation allows efficient storage and management of mapping information by organizing it into discrete, addressable units that can be independently accessed and updated without affecting the entire mapping structure.
Solution Approach 2:
The map data structure serves multiple functions simultaneously: it tracks logical-to-physical address mapping, manages original and copy block relationships, and enables the controller to determine which blocks are valid or closed. This multi-functionality reduces the need for separate data structures, thereby minimizing memory overhead while maintaining comprehensive data management capability.
3Reliability
If read operations alternate between original and copy blocks, then read disturbance is reduced, but access time increases
Solution Approach 1:
The patent implements periodic action by alternating read operations between original blocks and their corresponding copy blocks. The controller systematically switches between reading from the original block and the copy block in a periodic manner, which distributes the read disturbance across different physical blocks over time. This periodic alternation prevents excessive read disturbance accumulation in a single block while managing access time through predictable, patterned operations.
Data Source
AI summary
A memory system includes a memory device including a plurality of memory blocks, and a controller for controlling the memory device. The controller stores user data in an original block selected among the memory blocks. When the original block becomes a closed block, the controller generates a copy block by copying each page of the original block into a page having the same page address of a free block among the memory blocks, and stores map data associated with the user data in the memory device, the map data including a logical address of the user data, an address of the original block, an address of the copy block, and a common page address. The common page address is a page address which is in common in the original block and the copy block. In embodiments, the controller limits the number of copy blocks according to a configurable copy level.