RAID Parity Page Ratio for Flash Memory Reliability
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Solution Overview
Problem
Existing data storage devices, particularly flash memory, face chronic data errors and increased error rates due to repeated use, which existing methods such as bad block management and wear leveling struggle to efficiently address.
Innovation Solution
A method and device that determine a RAID parity page ratio based on control management information, such as erase count and error frequency, to dynamically allocate parity data in memory blocks, enhancing data reliability during write operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If flash memory is used for data storage, then storage capacity and portability are improved, but data reliability deteriorates due to chronic data errors and increased error rates from repeated use
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-allocating parity pages based on erase count thresholds before data write operations occur. The controller determines in advance which memory blocks need parity protection by checking their erase counts, and pre-assigns parity pages accordingly. This proactive approach ensures that parity protection is already in place before data errors can occur, rather than reacting after errors happen.
Solution Approach 2:
The patent implements local quality by applying different parity protection strategies to different memory blocks based on their individual erase counts and error characteristics. Memory blocks with higher erase counts receive more aggressive parity protection (lower parity page ratios), while blocks with lower erase counts receive standard protection. This localized differentiation optimizes reliability without uniformly increasing protection across all storage space.
2Reliability
If parity data is written in every memory block, then data reliability is improved, but storage space consumption increases
Solution Approach 1:
The patent applies local quality by differentiating parity protection levels across memory blocks based on their erase counts. Blocks with low erase counts receive standard parity protection, while blocks with high erase counts receive enhanced parity protection with lower parity page ratios. This ensures that storage space is allocated efficiently, providing extra protection only where needed rather than uniformly across all blocks.
Solution Approach 2:
The patent implements dynamics by making the parity page ratio adaptive and variable rather than fixed. The controller dynamically adjusts the parity page ratio based on real-time monitoring of erase counts and error rates in different memory blocks. This dynamic adjustment allows the system to optimize the balance between reliability and storage space utilization as storage conditions change over time.
3Device complexity
If fixed parity page ratio is used, then device complexity is reduced, but adaptability to varying error rates deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed parity page ratio to a dynamic, adaptive ratio that changes based on monitored conditions. The controller continuously monitors erase counts and error rates in memory blocks and adjusts the parity page ratio accordingly. This dynamic approach maintains relatively simple control logic while achieving high adaptability to varying storage conditions and error characteristics.
Solution Approach 2:
The patent implements feedback by establishing a closed-loop control system that monitors actual error rates and erase counts, then uses this information to adjust parity page ratios. The controller receives feedback data from memory block status monitoring, processes this information to determine optimal parity protection levels, and applies these adjustments to future write operations. This feedback mechanism enables the system to adapt to changing conditions without requiring complex predetermined rules for every scenario.
Data Source
AI summary
A data storage device and a method of managing data in the data storage device to improve data reliability are provided. In the method of managing data, one of control management information about a memory block of nonvolatile memory in which data will be written and control management information about the data are received. A redundant array of independent disks (RAID) parity page ratio is determined according to the control management information. When a data write operation mode is performed, parity data is written in a parity page of the memory block according the RAID parity page ratio. According to some embodiments of the inventive concepts, since a RAID parity page ratio is selectively determined according to control management information, reliability of data is secured or increased.