Read Leveling in Memory Devices to Mitigate Read Disturbance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As memory devices are scaled down, they become more susceptible to read disturbance due to intensive read operations, leading to reduced reliability and increased need for frequent data refreshing, which degrades system performance.
Innovation Solution
A read leveling method that involves determining block and page read counts in memory devices, identifying 'hot' data, and moving it to other blocks to alleviate read disturbance, using both coarse-grained and fine-grained counters to manage data distribution across multiple memory blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If memory device size is scaled down, then device integration is improved, but read disturbance susceptibility increases
Solution Approach 1:
The patent divides the memory device into multiple memory blocks (first memory block, second memory block, etc.) and further segments each block into multiple pages. This segmentation allows hot data to be isolated and moved between specific blocks, preventing read disturbance from affecting the entire memory device and enabling localized management of read-intensive data.
Solution Approach 2:
The patent introduces a new dimension of data management by implementing a hierarchical counter system (block-level coarse-grained counters and page-level fine-grained counters) that tracks read counts across multiple dimensions. This enables the system to identify and manage hot data in both block and page levels, adding complexity to the management structure but providing more granular control over read disturbance.
2Reliability
If frequent data refreshing is performed, then data reliability is improved, but system performance deteriorates
Solution Approach 1:
The patent performs preliminary action by proactively identifying hot data through counter tracking before read disturbance becomes problematic. When a block or page reaches a threshold read count, the system preemptively moves the hot data to a different block, preventing the need for frequent corrective refreshing operations and maintaining data reliability while reducing performance impact.
Solution Approach 2:
The patent implements feedback mechanisms through coarse-grained and fine-grained counters that continuously monitor read counts. This feedback enables the system to dynamically identify hot data and trigger data movement operations only when necessary (when thresholds are exceeded), rather than performing frequent blanket refreshing operations, thus maintaining reliability while optimizing performance.
3Reliability
If block and page read counts are tracked and hot data is moved, then read disturbance is reduced, but device complexity increases
Solution Approach 1:
The patent segments the counting mechanism into two distinct levels: block-level coarse-grained counters and page-level fine-grained counters. This segmentation allows the system to manage complexity by handling different granularities separately - the coarse counter identifies candidate blocks for hot data, while the fine counter identifies specific hot pages within those blocks, making the overall complex task more manageable.
Solution Approach 2:
The patent applies local quality by implementing fine-grained counting and data movement only where necessary (in blocks identified as containing hot data by the coarse counter), rather than uniformly across the entire memory device. This localized approach reduces the overall complexity burden by concentrating detailed management efforts only in affected regions.
Data Source
AI summary
A read leveling method for a memory device is provided. The memory device includes a first memory block and at least a second memory block. The read leveling method includes the following steps. Determining whether a block read count of the first memory block is larger than or equal to a first threshold. Detecting a page read count of a page of the first memory block when the block read count of the first memory block is larger than or equal to the first threshold. Determine whether the block read count of the first memory block is larger than or equal to a second threshold. Move data of one of the page of the first memory block to a page of the second memory block when the block read count of the first memory block is larger than or equal to the second threshold.