Flash Memory Controller Physical Block Recording Table Garbage Collection

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Solution Overview

Problem

The increasing size of blocks and data pages in flash memory modules leads to a significant increase in address information data, resulting in inefficient storage space usage and processing efficiency due to numerous invalid reading operations during garbage collection operations.

Innovation Solution

A method is introduced that builds a physical block recording table corresponding to a logical to physical (L2P) mapping table, allowing the flash memory controller to determine valid or invalid data pages efficiently by referencing this table instead of repeatedly reading the L2P mapping table from the flash memory module during garbage collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the block size and number of data pages are increased, then the storage capacity is improved, but the amount of address information increases significantly, leading to more invalid reading operations and reduced processing efficiency

Engineering Contradiction:

Improvestorage capacityVSAvoidprocessing efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent segments the address information management by introducing a physical block recording table that tracks which physical blocks contain valid L2P mapping entries. This segmentation allows the system to process only relevant blocks during garbage collection, rather than scanning all blocks, thereby maintaining processing efficiency despite increased storage capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by pre-recording physical block information in the physical block recording table before garbage collection operations. This advance preparation enables the controller to quickly identify which blocks contain valid data without performing invalid reading operations during the actual garbage collection process.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If the block size and number of data pages are increased, then the storage capacity is improved, but the amount of address information increases, resulting in more invalid reading operations and increased memory usage

Engineering Contradiction:

Improvestorage capacityVSAvoidstorage space

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The physical block recording table segments the address information into two parts: the L2P mapping table for logical-to-physical address translation and the physical block recording table for tracking valid physical blocks. This segmentation reduces the amount of address information that needs to be read and processed during garbage collection, thereby reducing storage space consumption for address information.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a simplified copy of block validity information in the physical block recording table, which contains only the essential physical block identifiers. This copying approach avoids storing redundant address information while maintaining the ability to efficiently determine data page validity.

Inventive Principle:

Principle #26Copying

3Measurement precision

If the L2P mapping table is read for every data page determination during garbage collection, then accurate valid/invalid determination is achieved, but numerous invalid reading operations occur, reducing processing efficiency

Engineering Contradiction:

Improvedata page validity determination accuracyVSAvoidgarbage collection processing efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary action by pre-populating the physical block recording table with information about which physical blocks contain valid L2P mapping entries. During garbage collection, the controller first checks this table to determine whether to read the L2P mapping table, thereby avoiding invalid reading operations while maintaining accurate data page validity determination.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of reading the L2P mapping table for every data page determination (the conventional approach), the patent inverts the logic by first checking the physical block recording table to see if reading the L2P mapping table is necessary. This inversion eliminates unnecessary reading operations while preserving determination accuracy.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10606744B2Method for accessing flash memory module and associated flash memory controller and electronic device

Publication Date: 2020.03.31 SILICON MOTION INC

AI summary

The present invention provides a method for accessing a flash memory module, wherein the method comprises: building a physical block recording table corresponding to a logical address to physical address (L2P) mapping table, wherein the physical block recording table records at least one block whose physical address is recorded in the L2P mapping table; and when a specific block within the flash memory module is under a garbage collection operation, for a data page of the specific block whose logical address is within the L2P mapping table, referring to the physical block recording table to determine if reading the L2P mapping table from the flash memory module or not, for determining the data page to be valid or invalid.