Memory Encoding Rules for Extending Flash Write Life

Solution Overview

Problem

As the usage time of memory devices increases, memory blocks become damaged, leading to a write protect state where new data cannot be written, reducing the device's lifetime without impacting normal usage.

Innovation Solution

A memory management method that dynamically updates the encoding rule for physical erasing units by adjusting the code rates of different types of physical programming units based on error estimating information, allowing for extended device lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data is stored using a default code rate in all physical programming units, then the storage capacity is maximized, but the reliability deteriorates as memory blocks become damaged over time

Engineering Contradiction:

Improvestorage capacityVSAvoiddata integrity

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the code rate configuration across different types of physical programming units within the same physical erasing unit. First-type physical programming units use a first code rate while second-type physical programming units use a second code rate, allowing each type to be optimized for its specific characteristics and error susceptibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the code rate parameter based on the type of physical programming unit. By configuring different code rates (first code rate for first-type units, second code rate for second-type units) instead of using a uniform default code rate, the system adapts to varying error characteristics of different memory cell types within the same erasing unit.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the code rate is increased to improve error correction, then the reliability improves, but the storage capacity decreases due to more overhead bits

Engineering Contradiction:

Improveerror correction capabilityVSAvoidstorage capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by differentiating the code rate configuration across different types of physical programming units within the same physical erasing unit. First-type physical programming units use a first code rate while second-type physical programming units use a second code rate, allowing each type to be optimized for its specific characteristics and error susceptibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the code rate parameter based on the type of physical programming unit. By configuring different code rates (first code rate for first-type units, second code rate for second-type units) instead of using a uniform default code rate, the system adapts to varying error characteristics of different memory cell types within the same erasing unit.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a uniform encoding rule is used for all physical programming units, then the device complexity is minimized, but the lifetime deteriorates as damaged blocks cannot be compensated

Engineering Contradiction:

Improveencoding rule complexityVSAvoiddevice lifetime

Core Design Contradiction:

Device complexityVSDuration of action of moving object

Solution Approach 1:

The patent segments the physical programming units into different types (first-type and second-type) based on their error characteristics and assigns different encoding rules to each segment. This segmentation allows the system to apply tailored error correction strategies to different memory cell types, extending the overall device lifetime by compensating for damaged blocks more effectively.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic encoding rule configuration that adapts to the specific characteristics of each physical programming unit type. Rather than using a static uniform encoding rule, the system dynamically selects appropriate code rates based on the unit type, enabling better adaptation to aging and damage patterns throughout the device's operational life.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9941907B2Memory management method, memory storage device and memory control circuit unit

Publication Date: 2018.04.10 SHENZHEN EPOSTAR ELECTRONICS LTD

AI summary

A memory management method, a memory storage device and a memory control circuit unit are provided. The method includes: configuring a default encoding rule for a first physical erasing unit which includes encoding data to be stored to the first physical erasing unit based on a default code rate; configuring a first encoding rule, for the first physical erasing unit according to error estimating information of the first physical erasing unit, which includes encoding data to be stored to a first-type physical programming unit and a second-type physical programming unit belonging to the first physical erasing unit based on a first code rate and a second code rate respectively, where a value of the first code rate is greater than a value of the default code rate, and a value of the second code rate is less than the value of the default code rate.