Flash Memory Block Management for Wear Uniformity

Solution Overview

Problem

Flash memory systems face uneven wear and tear of physical blocks, leading to premature failure due to differential usage and replacement, resulting in reduced lifespan even when some blocks remain unused.

Innovation Solution

Implementing a block management method that groups physical blocks into data, spare, and replacement areas, with physical unit switches between these areas to evenly distribute usage and wear, utilizing a flash memory controller with a microprocessor and memory management module to manage these operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If physical blocks are repeatedly programmed and erased, then the flash memory can store and retrieve data, but the wear of the physical blocks increases leading to damaged blocks

Engineering Contradiction:

Improvedata storage and retrieval capabilityVSAvoidphysical block durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The flash memory is divided into multiple physical units (PU0-PU7), each containing multiple physical blocks. This segmentation allows the system to manage wear at the physical unit level rather than individual block level, enabling more flexible wear distribution strategies across the memory structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically changes the operational state parameters of physical units by switching them between different areas (data area, spare area, replacement area) based on wear levels. This parameter change approach allows the system to adapt to varying wear conditions and extend overall memory lifespan.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If damaged physical blocks are replaced by new blocks from the replacement area, then the system can continue operating, but the wear distribution becomes uneven and physical units become insufficient

Engineering Contradiction:

Improvesystem operational continuityVSAvoidwear distribution uniformity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system implements dynamic management of physical units by switching them between data area, spare area, and replacement area based on real-time wear conditions. This dynamic approach ensures that wear is distributed evenly across all physical units over time, preventing any single unit from becoming excessively worn while maintaining system operational continuity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system continuously monitors the wear status of physical blocks and uses this feedback to make informed decisions about which physical units to switch between areas. This feedback mechanism ensures that replacement operations are performed strategically to maintain uniform wear distribution rather than simply replacing damaged blocks with new ones.

Inventive Principle:

Principle #23Feedback

3Reliability

If physical units are switched between data area and spare area, then wear can be distributed more evenly, but the system complexity increases

Engineering Contradiction:

Improvewear distribution uniformityVSAvoidblock management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flash memory is divided into multiple physical units (PU0-PU7), each containing multiple physical blocks. This segmentation allows the system to manage wear at the physical unit level rather than individual block level, enabling more flexible wear distribution strategies across the memory structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements dynamic management of physical units by switching them between data area, spare area, and replacement area based on real-time wear conditions. This dynamic approach ensures that wear is distributed evenly across all physical units over time, preventing any single unit from becoming excessively worn while maintaining system operational continuity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8275931B2Block management method for flash memory, and storage system and controller using the same

Publication Date: 2012.09.25 EMTOPS ELECTRONICS CORP

AI summary

A block management method for a flash memory of a storage system is provided, wherein the flash memory includes a plurality of physical blocks. The block management method includes grouping the physical blocks into a plurality of physical units, and grouping the physical units into a data area, a spare area, and a replacement area. The block management method further includes performing a first physical unit switch which switches the physical units between the data area and the spare area, and performing a second physical unit switch which switches the physical units between the spare area and the replacement area. Therefore, the block management method can uniformly use the physical blocks and thereby effectively prolong a lifespan of the storage system.