Storage Device Sub-Blocks with SLC Data and Dense Recovery Storage
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Solution Overview
Problem
Existing non-volatile memory devices face challenges in maintaining data integrity and reliability due to high integration levels, leading to issues like uncorrectable error conditions (UECC) and inefficient storage capacity utilization, particularly in managing metadata and user data.
Innovation Solution
The storage device employs a non-volatile memory device with memory blocks divided into sub-blocks, programming original data in a first level cell mode and mirrored or parity data in a second level cell mode with higher bit density, reducing storage space required for recovery data and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-volatile memory devices are highly integrated to improve storage capacity, then storage density increases, but data reliability deteriorates due to uncorrectable error conditions
Solution Approach 1:
The memory block is divided into multiple sub-blocks (first sub-block and second sub-block) that can be independently managed. This segmentation allows the system to isolate errors to specific sub-blocks and apply different storage modes to different sub-blocks, thereby maintaining overall data reliability while preserving high storage capacity utilization.
Solution Approach 2:
Different sub-blocks are assigned different storage modes (SLC mode for original data, MLC/TLC/QLC mode for recovery data) based on their specific functions. The first sub-block stores original data with high reliability requirements in SLC mode, while the second sub-block stores recovery data in higher density modes, optimizing both reliability and storage efficiency locally within each sub-block.
2Reliability
If recovery data is stored in the same memory block as original data, then data reliability improves through faster error recovery, but storage capacity utilization deteriorates
Solution Approach 1:
The memory block is segmented into first and second sub-blocks, where the first sub-block stores original data and the second sub-block stores recovery data. This segmentation enables independent management of original and recovery data, allowing the system to maintain high reliability through localized recovery capability while optimizing overall storage capacity utilization by efficiently allocating space for recovery data within the same block.
Solution Approach 2:
The system changes the storage mode parameter between sub-blocks: the first sub-block uses SLC mode for original data while the second sub-block uses MLC, TLC, or QLC mode for recovery data. This parameter change allows recovery data to be stored more efficiently with higher density, reducing the capacity overhead associated with storing recovery data while maintaining fast recovery capability within the same memory block.
3Quantity of substance
If higher bit density modes are used for recovery data, then storage space efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
Different sub-blocks are assigned different storage modes (SLC for original data, MLC/TLC/QLC for recovery data) based on their specific functions. This local quality approach allows the system to use higher bit density modes for recovery data where manufacturing precision can be managed, while maintaining SLC mode for original data where maximum reliability is required, thus optimizing storage space efficiency without excessively increasing manufacturing precision requirements across the entire device.
Data Source
AI summary
A storage device includes: a non-volatile memory device comprising a plurality of memory blocks in which a plurality of cell strings are divided into a plurality of sub-blocks disposed in a vertical direction, wherein in each of the plurality of cell strings, a string select transistor, a plurality of memory cells and a ground select transistor are disposed in series, in the vertical direction, between a bit line and a source line; and a storage controller configured to program original data into at least one first sub-block of the plurality of sub-blocks in a first level cell mode, and program recovery data for recovering the original data into at least one second sub-block of the plurality of sub-blocks in a second level cell mode having a bit density greater than that of the first level cell mode, in a first memory block of the plurality of memory blocks.