Memory Controller Data Routing for Bad Word Line Management
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Solution Overview
Problem
Memory systems face performance degradation due to bad word lines, which inefficiently use super memory blocks and lead to uncorrectable errors during data writing, especially when using interleaving methods.
Innovation Solution
A memory system and operating method that determine whether to write data to a super memory block with bad word lines or one without, based on the size of the target data, optimizing data distribution to minimize performance degradation by using a threshold size to decide between two types of super memory blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is written to super memory blocks containing bad word lines, then storage capacity is improved, but write performance degrades and uncorrectable errors occur
Solution Approach 1:
The patent changes the parameter of data size by comparing it against a threshold value. When data size is below the threshold, it is written to super memory blocks with bad word lines; when above, it is written to super memory blocks without bad word lines. This dynamic parameter-based decision resolves the contradiction by adapting the storage location to the data characteristics.
Solution Approach 2:
The patent applies different quality standards to different portions of data based on size. Small data portions are directed to super memory blocks with bad word lines (utilizing otherwise wasted capacity), while large data portions are directed to clean super memory blocks (ensuring performance and reliability). This local differentiation resolves the contradiction between capacity utilization and performance.
2Quantity of substance
If data is written to super memory blocks with bad word lines, then storage efficiency is improved, but reliability deteriorates due to uncorrectable errors
Solution Approach 1:
The patent uses data size as a parameter to determine the destination super memory block. By setting an appropriate threshold, small data writes can tolerate the reduced reliability of blocks with bad word lines, while large data writes maintain high reliability by using clean blocks. This parameter-based approach balances efficiency and reliability.
Solution Approach 2:
The patent applies a partial strategy where only a portion of the data (small writes below threshold) is directed to super memory blocks with bad word lines, while the majority (large writes above threshold) go to clean blocks. This partial application of the risky strategy minimizes reliability impact while maintaining storage efficiency.
3Quantity of substance
If threshold size is set low, then more data can be written to super memory blocks with bad word lines improving capacity utilization, but write performance degradation increases
Solution Approach 1:
The patent dynamically adjusts the decision boundary (threshold size) based on the characteristics of super memory blocks. By optimizing this parameter, the system achieves the best balance between capacity utilization and write performance. The threshold acts as a control parameter that can be tuned to match system conditions.
4Productivity
If threshold size is set high, then write performance is maintained by writing to clean super memory blocks, but capacity utilization of super memory blocks with bad word lines decreases
Solution Approach 1:
The patent optimizes the threshold size parameter to achieve the desired balance. By adjusting this single parameter, the system can shift between prioritizing performance (higher threshold) and prioritizing capacity utilization (lower threshold), providing flexibility to adapt to different operational requirements.
Data Source
AI summary
Embodiments of the present disclosure relate to a memory system and a method for operating the memory system. According to embodiments of the present disclosure, a memory system may determine a target write data which is to be written to one of a plurality of super memory blocks, and may write the target write data based on a size of the target write data, to a first super memory block which includes at least one bad word line or a second super memory block which includes no bad word line.