Flash Memory Mapping Table Reconstruction for Boot Time Reduction
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Solution Overview
Problem
The initialization of flash memory requires a long boot time due to the need to read and reorganize physical sectors, leading to performance deterioration as existing technologies centralize erase operations, reducing the lifespan of flash memory.
Innovation Solution
An apparatus and method that secure a mapping sector for recording user data and logical sector relations, determining if user data is recorded at a predetermined position, and reorganize the mapping table by searching for last-recorded mapping information to minimize access and reorganization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flash memory reads all physical sectors to reorganize mapping information during initialization, then the mapping table can be correctly reconstructed, but the boot time increases significantly
Solution Approach 1:
The patent extracts only the necessary mapping information from physical sectors during initialization, rather than reading all physical sectors. The FTL controller selectively retrieves mapping entries that are actually needed to reconstruct the mapping table, eliminating redundant read operations and significantly reducing boot time while maintaining reconstruction accuracy
Solution Approach 2:
The patent performs preliminary organization of mapping information during normal operation, maintaining an optimized mapping structure that can be quickly reconstructed. By preparing mapping information in advance and organizing it in a retrieval-friendly format, the system enables fast boot-time reconstruction without needing to read and process all physical sectors
2Device complexity
If the flash memory performs erase operations in centralized blocks, then the mapping reorganization can be simplified, but the flash memory lifespan is reduced
Solution Approach 1:
The patent segments the flash memory into multiple blocks and distributes erase operations across these blocks rather than concentrating them in centralized areas. The FTL controller manages mapping to balance erase cycles across different blocks, preventing any single block from being over-erased and thereby extending the overall flash memory lifespan while maintaining manageable reorganization complexity
Solution Approach 2:
The patent changes the mapping parameters and block allocation strategies to distribute erase operations more evenly across the flash memory. By adjusting how data is mapped and which blocks are selected for erasure, the system reduces erase centralization and extends flash memory durability without significantly complicating the reorganization process
3Reliability
If the flash memory uses erase-before-write operation, then data integrity is maintained, but the input/output operation time increases
Solution Approach 1:
The patent performs preliminary actions by pre-allocating clean blocks and preparing mapping information before write operations are needed. The FTL controller maintains a pool of ready-to-write blocks that have already been erased and are mapped to available logical addresses, allowing write operations to proceed immediately without waiting for erase cycles, thus improving I/O speed while maintaining data integrity
Solution Approach 2:
The patent substitutes the sequential erase-then-write mechanical process with a parallel architecture where multiple clean blocks are prepared in advance. Instead of erasing one block at a time before writing, the system maintains multiple pre-erased blocks ready for simultaneous or rapid sequential writes, effectively decoupling the erase operation from the write operation timeline and improving overall I/O throughput
Data Source
AI summary
An apparatus and method for reorganizing mapping information in a flash memory are provided. The apparatus includes a sector-managing module that secures a mapping sector where mapping information is recorded in a physical unit, and determines whether user data is recorded up to a sector located in a predetermined position, and a mapping-information-recording module that records the mapping information in the mapping sector according to a result of the determination. Here, the mapping information includes a relation of a physical sector storing the user data and a logical sector corresponding to the physical sector.