Non-volatile Memory Wear Prediction Using Fermi-Dirac Distribution

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current non-volatile memory systems face challenges in efficiently managing and predicting the failure of memory blocks due to high error rates, which can lead to data corruption and reduced system reliability, especially when dealing with low-probability events that require significant time and resources for accurate prediction.

Innovation Solution

The implementation of a statistical analysis method using a Fermi-Dirac distribution to extrapolate from a small sample size, allowing for rapid and cost-effective prediction of low-probability events such as target Failed Bit Counts (FBC) in non-volatile memory systems, enabling proactive management of wear leveling, garbage collection, and voltage adjustments within the memory system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional statistical methods are used to predict memory block failures, then measurement precision can be achieved with large sample sizes, but time consumption and computational resources increase significantly

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the mathematical parameters and approach by using Fermi-Dirac distribution instead of traditional statistical methods. This allows the system to achieve accurate predictions of low-probability events (memory block failures) by transforming the problem into a different mathematical framework that requires significantly fewer samples and computational resources while maintaining prediction accuracy.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If traditional statistical methods are used to predict memory block failures, then measurement precision can be achieved, but computational resources and cost increase significantly

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational resources
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the mathematical parameters and approach by using Fermi-Dirac distribution instead of traditional statistical methods. This allows the system to achieve accurate predictions of low-probability events (memory block failures) by transforming the problem into a different mathematical framework that requires significantly fewer samples and computational resources while maintaining prediction accuracy.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If wear leveling and garbage collection are performed frequently to manage memory block failures, then system reliability improves, but productivity and operational efficiency decrease

Engineering Contradiction:
Improvesystem reliabilityVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by predicting which memory blocks are likely to fail before they actually do, using the Fermi-Dirac distribution to estimate failure probabilities based on current wear patterns. This allows the system to perform wear leveling and garbage collection proactively on blocks that are most at risk, rather than reactively after failures occur, thereby maintaining reliability while reducing unnecessary operations and improving overall productivity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10802911B2Non-volatile storage with wear-adjusted failure prediction
Publication Date: 2020.10.13 SANDISK TECHNOLOGIES LLC
  • US10802911B2 patent drawing
  • US10802911B2 patent drawing
  • US10802911B2 patent drawing

AI summary

A non-volatile storage apparatus includes a set of non-volatile memory cells and one or more control circuits in communication with the set of non-volatile memory cells. The one or more control circuits are configured to collect failure bit counts (FBCs) for data read from the set of non-volatile memory cells in a first time period and manage the set of non-volatile memory cells according to a probability of occurrence of a target FBC in a second time period that is subsequent to the first time period. The probability of occurrence of the target FBC during the second time period is calculated from a model of FBC distribution change of the set of non-volatile memory cells.