F2H Mapping Table Recovery During Power Loss

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Solution Overview

Problem

Data storage devices using non-volatile memory face challenges in generating and storing a flash physical-to-host logical address (F2H) mapping table quickly during power drop/loss events, leading to potential data loss due to the complexity and size of the mapping table.

Innovation Solution

The method involves generating primary and secondary F2H mapping tables that record only the correspondence of data in the last data-containing page and previous pages, reducing the amount of data and time required for generation, and storing these tables in designated blocks with better data retention capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complete F2H mapping table is generated and stored during power drop/loss events, then data completeness is improved, but generation time and data size increase

Engineering Contradiction:

Improvedata completenessVSAvoidgeneration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts only the critical portions of the F2H mapping table that are necessary for data recovery after power loss. Instead of generating and storing the complete mapping table, the system identifies and stores only the mapping information for the active block and its related pages, significantly reducing generation time and storage requirements while maintaining sufficient data completeness for recovery operations.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If a complete F2H mapping table is generated and stored during power drop/loss events, then data completeness is improved, but the amount of data to be stored increases

Engineering Contradiction:

Improvedata completenessVSAvoiddata size

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies extraction by removing unnecessary data from the F2H mapping table. Only the essential mapping information for the active block and its related pages is retained and stored, while the rest of the mapping table is omitted. This reduces the data size significantly while preserving the critical information needed for data recovery after power loss events.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If the F2H mapping table is stored in regular blocks, then storage simplicity is improved, but data retention capability deteriorates

Engineering Contradiction:

Improvestorage simplicityVSAvoiddata retention capability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by differentiating the storage characteristics for different types of data. The F2H mapping table, which requires high data retention capability, is stored in specific designated blocks with superior retention properties rather than using uniform storage for all data. This localized approach ensures critical mapping information is preserved reliably while maintaining overall storage efficiency.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10579483B2Storing a compact flash physical-to-host logical address mapping table on power loss

Publication Date: 2020.03.03 SILICON MOTION INC

AI summary

A data storage method includes steps of: selecting an active block to store data from a host; determining whether a power drop/loss event has occurred; when it is determined that a power drop/loss event has occurred, recording an index of the active block and an index of a last data-containing page in the active block; generating a primary F2H mapping table; and writing the primary F2H mapping table, the index of the active block and the index of the last data-containing page into a designated block. A data storage device and a data recovery program are also provided.