Flash Memory Controller Temperature-Based Data Placement

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Solution Overview

Problem

The repetition of data erasing and writing in flash memory leads to deterioration of the insulating film, causing data loss over time, and existing refresh processes degrade reading and writing performance by requiring data read and rewrite operations.

Innovation Solution

A storage device with a controller that measures temperature and determines the rewriting interval for data, allowing data to be written to flash memories with corresponding temperature conditions to optimize refresh intervals and prevent data loss without degrading host performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a refresh process is performed to prevent data loss, then data integrity is maintained, but reading and writing performance of the host is degraded

Engineering Contradiction:

Improvedata integrityVSAvoidreading and writing performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary actions by writing data to multiple flash memory devices with different temperature characteristics and rewriting intervals in advance. By distributing data across devices with varying durability under different temperature conditions, the system prepares for potential data loss scenarios without requiring immediate refresh operations, thus maintaining host performance while ensuring data integrity through redundant storage strategies.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If data is rewritten frequently to prevent data loss, then data retention is improved, but the insulating film deteriorates faster

Engineering Contradiction:

Improvedata retentionVSAvoidinsulating film lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system applies local quality by storing data across multiple flash memory devices with different temperature characteristics and rewriting intervals. Each device operates under optimized local conditions (temperature and rewrite frequency), allowing data to be protected against data loss while minimizing overall insulating film deterioration by distributing wear across devices with varying durability profiles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes parameters by utilizing flash memory devices with different temperature characteristics and rewriting intervals. By varying the operational parameters (temperature exposure and rewrite frequency) across multiple devices, the system achieves data protection without subjecting any single device to excessive stress, thereby extending the overall system lifespan while maintaining data retention.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the refresh process is performed regularly, then data loss is prevented, but host operations are suspended

Engineering Contradiction:

Improvedata retentionVSAvoidhost operation suspension

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by distributing data across multiple flash memory devices with different rewriting intervals before data loss can occur. This proactive distribution strategy eliminates the need for suspended host operations during refresh, as the system relies on pre-configured redundant storage rather than active refresh interruptions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements self-service by using multiple flash memory devices with inherently different temperature characteristics and rewriting intervals. Each device autonomously maintains data under its optimal conditions, eliminating the need for centralized refresh operations that would suspend host services. The diversity of device characteristics provides built-in data protection without requiring active intervention.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach minimizes the likelihood of refresh processes that degrade performance, ensuring data integrity by writing data to flash memories with appropriate temperature conditions, thus extending device performance and lifespan.

Implementation Method 1

a sensor that measures a temperature of the nonvolatile semiconductor memories

Methodology Applied

Scientific EffectTemperature measurement:

Data Source

PatentUS9984731B2Storage device and storage method

Publication Date: 2018.05.29 KIOXIA CORP

AI summary

According to one embodiment, a storage device includes a plurality of nonvolatile semiconductor memories, a sensor and a controller. The sensor is configured to measure a temperature of the nonvolatile semiconductor memories. The controller is configured to receive data from a host, determine a rewriting interval of the data and write the data to, of the nonvolatile semiconductor memories, a nonvolatile semiconductor memory having a temperature corresponding to the rewriting interval.