Flash Memory Storage Device MLC SLC Segmentation

Solution Overview

Problem

Flash memory systems face inefficiencies in data access and storage due to the limitations of NAND flash memory, particularly with MLC and SLC types, where data update and erasure processes are time-consuming and lead to block wear-out, affecting access and power consumption.

Innovation Solution

A flash memory storage system that dynamically determines whether to store files in MLC or SLC NAND flash memory based on file size and characteristics, such as video or configuration files, using a control unit to manage data storage between the two types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If MLC NAND flash memory is used, then storage capacity and access speed are improved, but the number of access times decreases (shorter life)

Engineering Contradiction:

Improveaccess speedVSAvoidnumber of access times

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The flash memory storage device is segmented into two distinct types: MLC NAND flash memory for high-speed storage and SLC NAND flash memory for high-endurance storage. The controller segments the storage space into first storage space (MLC) and second storage space (SLC), allowing different types of data to be stored in different segments with appropriate characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the storage system are assigned different qualities based on data characteristics. Frequently accessed or critical data are stored in SLC with higher reliability, while less critical data are stored in MLC with higher capacity. The system locally optimizes storage quality according to specific data requirements.

Inventive Principle:

Principle #3Local quality

2Reliability

If SLC NAND flash memory is used, then the number of access times increases (longer life), but access speed decreases

Engineering Contradiction:

Improvenumber of access timesVSAvoidaccess speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The flash memory storage device is segmented into two distinct types: MLC NAND flash memory for high-speed storage and SLC NAND flash memory for high-endurance storage. The controller segments the storage space into first storage space (MLC) and second storage space (SLC), allowing different types of data to be stored in different segments with appropriate characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the storage system are assigned different qualities based on data characteristics. Frequently accessed or critical data are stored in SLC with higher reliability, while less critical data are stored in MLC with higher capacity. The system locally optimizes storage quality according to specific data requirements.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If data is updated in-place in flash memory, then write operations are simplified, but erasure time increases significantly (10-20 times longer than writing)

Engineering Contradiction:

Improvedata update operationVSAvoiderasure time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-erasing blocks before they are fully needed, and by pre-positioning data in optimal locations. The controller manages wear by preliminarily distributing write operations across different blocks, and by pre-cleaning unused blocks to reduce future erasure overhead.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller acts as an intermediary that manages the complexity of flash memory operations. It handles wear leveling, bad block management, and data relocation transparently, mediating between the host system and the physical constraints of flash memory to minimize erasure operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances access efficiency by optimizing storage based on file characteristics, extending the life of flash memory blocks and balancing power consumption and access speed.

Implementation Method 1

charges move across a floating gate relying on charge coupling which determines a threshold voltage of a transistor under the floating gate

Methodology Applied

Scientific EffectCharge coupling: Capacitance

Implementation Method 2

in response to an injection of electrons into the floating gate, the logical status of the floating gate turns from 1 to 0; on the contrary, in response to move electrons away from the floating gate, the logical status of the floating gate turns from 0 to 1

Methodology Applied

Scientific EffectElectron injection: Electron Beam

Data Source

PatentUS7934053B2Flash memory storage device for adjusting efficiency in accessing flash memory

Publication Date: 2011.04.26 GENESYS LOGIC INC

AI summary

A flash memory storage device for boosting efficiency in accessing flash memory is disclosed. The flash memory storage device provides a Multi-level cell (MLC) flash memory for storing data, a single-level cell (SLC) flash memory for storing data, and a control unit for determining whether to store a file into the MLC NAND flash memory or a SLC NAND flash memory based on the file's data characteristics.