Flash Memory Page Blankness Detection via Identification Region Segmentation

Solution Overview

Problem

Existing flash memory access methods are inefficient as they require reading all bits of a page to determine if it is blank, significantly degrading performance when most pages are blank.

Innovation Solution

A method where a controller reads a specific identification bit or byte from an identification region at the beginning of each page to determine if it is blank, allowing for efficient identification without reading the entire page.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the controller reads all bits of a page to determine whether it is blank, then the determination accuracy is ensured, but the access efficiency is significantly degraded

Engineering Contradiction:

Improvedetermination accuracyVSAvoidaccess efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the page structure into an identification region and a data region. The identification region contains specific bits (such as the first bit or last bit of each data byte) that serve as indicators of page blankness. By segmenting the page in this way, the controller can determine blankness by reading only the identification region rather than the entire page, thus resolving the contradiction between determination accuracy and access efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts the blankness determination information from the entire page content and concentrates it in the identification region. Specifically, certain bits in the identification region are set to specific values (e.g., all 1s for blank pages, not all 1s for non-blank pages) to indicate the blankness status. This extraction allows the controller to determine page blankness by reading only these specific bits rather than all page bits, thereby improving access efficiency while maintaining determination accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the controller reads all bits of a page to determine whether it is blank, then the blank page identification is accurate, but the access time is increased

Engineering Contradiction:

Improveblank page identification accuracyVSAvoidaccess time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-setting the identification region with specific bit patterns that indicate page blankness before the actual data operations occur. When a page is erased, the identification region is automatically set to a specific state (e.g., all 1s). When data is written, the identification region is updated to reflect the non-blank status. This preliminary setup allows the controller to quickly determine blankness without reading the entire page, thus reducing access time while maintaining identification accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the blankness determination information from the entire page content and concentrates it in the identification region. Specifically, certain bits in the identification region are set to specific values (e.g., all 1s for blank pages, not all 1s for non-blank pages) to indicate the blankness status. This extraction allows the controller to determine page blankness by reading only these specific bits rather than all page bits, thereby improving access efficiency while maintaining determination accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If the controller reads all bits of a page to determine whether it is blank, then the page status is accurately determined, but the performance during data copy operations is seriously degraded

Engineering Contradiction:

Improvepage status determination accuracyVSAvoiddata copy performance

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the page structure into an identification region and a data region. The identification region contains specific bits (such as the first bit or last bit of each data byte) that serve as indicators of page blankness. By segmenting the page in this way, the controller can determine blankness by reading only the identification region rather than the entire page, thus resolving the contradiction between determination accuracy and access efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by reading only the identification region (a small portion of the page) to determine page blankness, rather than reading the entire page. This partial reading approach provides sufficient information for blankness determination in most cases, significantly improving data copy performance while maintaining acceptable determination accuracy. The controller can then decide whether to read the full page content based on the identification region result.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8312205B2Method for identifying a page of a block of flash memory, and associated memory device

Publication Date: 2012.11.13 SILICON MOTION INC

AI summary

A memory device includes a flash memory and a controller. The flash memory includes a plurality of blocks, and each block includes a plurality of pages. The controller is utilized for reading a plurality of bits from an identification region of a page, and determining whether the page is blank or not according to the plurality of bits.