QLC NAND Block Sub-division for Wear Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
QLC NAND flash memory devices face challenges in extending the active lifetime of QLC blocks due to wear and error accumulation, leading to unusable pages beyond error correction capabilities.
Innovation Solution
A computer-implemented method and dynamic data adapter generator system that store data in SLC pages, divide QLC blocks into sub-blocks based on page health status, and copy SLC pages to QLC pages using device-internal cache registers, employing an error-count aware scheme to manage data placement and extend block lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If QLC blocks are used to increase storage density, then storage capacity is improved, but active lifetime is reduced due to wear and error accumulation
Solution Approach 1:
The QLC block is divided into multiple sub-blocks based on page health status. This segmentation allows the system to isolate and retire only the degraded sub-blocks while keeping the healthy sub-blocks operational, thereby extending the overall active lifetime of the QLC block while maintaining high storage capacity utilization.
Solution Approach 2:
The system performs preliminary health assessment and divides the QLC block into sub-blocks based on page health status before errors become critical. This proactive approach allows for early retirement of degraded sub-blocks, preventing error accumulation from compromising the entire block's reliability and extending usable lifetime.
2Reliability
If SLC pages are copied to QLC pages to extend lifetime, then reliability is improved, but device complexity increases
Solution Approach 1:
Device-internal cache registers are used as an intermediary to copy SLC pages to QLC pages. This intermediary mechanism simplifies the data management process by providing a direct copy path within the device, reducing the complexity of external data movement while improving reliability through redundant storage.
Solution Approach 2:
The system copies data from SLC pages to QLC pages using device-internal cache registers. This copying mechanism extends the lifetime of QLC blocks by creating redundant copies of data in more reliable SLC storage, thereby improving overall block reliability without requiring complex external data management systems.
3Duration of action of stationary object
If QLC blocks are divided into sub-blocks based on health status, then usable lifetime is extended, but manufacturing precision requirements increase
Solution Approach 1:
The system applies local quality assessment by evaluating and dividing the QLC block into sub-blocks based on the health status of individual pages. This localized approach allows for precise identification of degraded areas while maintaining overall block functionality, extending usable lifetime without requiring excessive manufacturing precision across the entire block.
Data Source
AI summary
A technique for writing data to pages in a QLC block of a QLC NAND flash memory device, where the device comprises a plurality of SLC pages organized in SLC blocks and a plurality of QLC pages organized in QLC blocks. The technique comprises storing received data in SLC pages, dividing equally a QLC block in a predefined number of sub-blocks according to a corresponding QLC page health status of the pages of the QLC block. Upon determining that SLC pages are to be copied from SLC pages to QLC pages, copying device-internal the respective SLC pages to the sub-blocks of the QLC block using device-internal cache registers, where the copying is based on an error-count aware scheme.