Memory Block Stripe Skew Offsets for Bad Block Locality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory devices face challenges in achieving consistent performance and reliability due to bad block locality, which affects the efficiency of block stripe configurations, leading to suboptimal performance metrics and increased latency.
Innovation Solution
A method for selecting a skew offset value based on the distribution of bad blocks across dies within a memory device, which involves looping through candidate skew offset values and disqualifying block stripes with excessive bad blocks, ensuring a higher quantity of valid blocks per die, thereby improving performance consistency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional block stripe configurations are used without skew offset optimization, then device complexity is reduced, but reliability deteriorates due to bad block locality affecting performance consistency
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal skew offset values in a lookup table during device initialization or manufacturing. The controller retrieves pre-determined skew offset values based on block stripe parameters, avoiding real-time complex calculations and achieving both high reliability and low complexity operation during normal use
Solution Approach 2:
The patent introduces skew offset values as intermediary parameters that mediate between block stripe configuration and bad block distribution. These offset values act as a buffer layer that decouples the direct relationship between block indexing and physical block locations, allowing the system to achieve reliable performance without complex real-time analysis
2Reliability
If skew offset optimization with extensive candidate testing is performed, then reliability is improved through better block stripe configuration, but loss of time increases due to the looping and disqualification process
Solution Approach 1:
The patent performs skew offset optimization in advance during device initialization or manufacturing, storing the results in a lookup table. This preliminary action shifts the time-consuming optimization process to a setup phase, allowing rapid retrieval during normal operation and eliminating the time loss from repeated optimization cycles
Solution Approach 2:
The patent tests a finite set of candidate skew offset values (e.g., 0-255) rather than all possible configurations. By limiting the search space to a manageable number of candidates and using disqualification criteria to eliminate poor options early, the system achieves sufficient reliability improvement without exhaustive time-consuming analysis
3Productivity
If block stripes include blocks from multiple planes and dies, then productivity is improved through parallel access, but reliability worsens due to increased exposure to bad blocks across multiple dies
Solution Approach 1:
The patent applies local quality by selecting blocks from specific planes and dies based on their individual quality characteristics and bad block distributions. The skew offset optimization process identifies combinations of planes and dies that provide good parallel access while avoiding regions with high bad block density, creating locally optimized block stripe configurations
Solution Approach 2:
The patent uses skew offset values as intermediary parameters to coordinate block selection across multiple planes and dies. These offsets mediate the parallel access operation by adjusting the block indexing to account for variations in bad block distribution across different dies, enabling reliable parallel access without simply aggregating all available blocks
Data Source
AI summary
Methods, systems, and devices for block stripe building for a memory device are described. Selection of a skew offset value for configuration of block stripes at a memory device may be based on a relative distribution of bad blocks across memory devices within block stripes. For selecting the skew offset value, a manufacturing system may loop through a set of candidate skew offset values. For each skew offset value, the manufacturing system may loop through each block stripe formed using the skew offset value, and may maintain a counter that identifies a quantity of dies in the block stripe where a quantity of bad blocks in the die exceeds a threshold. The manufacturing system may disqualify block stripes based on the counters satisfying thresholds. The manufacturing system may select a skew offset value for configuration of block stripes based on quantities of disqualified block stripes for each skew offset value.