Flash Memory Conversion Table Recovery via Chronological Sorting
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Solution Overview
Problem
Existing data management systems in flash memory devices require extensive data retrieval to reestablish the conversion table when it is damaged, leading to prolonged recovery times and potential data loss due to incomplete block writing processes.
Innovation Solution
A storage device that writes logical addresses and old/new information page-by-page into flash memory, allowing for the reestablishment of the conversion table by sorting and aligning physical addresses based on chronological writing times, enabling efficient and simple table reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire data is read out to reestablish the conversion table when it is damaged, then the conversion table can be reconstructed, but the recovery time becomes excessively long
Solution Approach 1:
The patent extracts only the necessary information (logical addresses and old/new markers) from the data pages during the normal writing process, storing this metadata separately in the conversion table. When recovery is needed, only this extracted metadata needs to be processed, not the entire data set, thereby dramatically reducing recovery time while maintaining reliability.
Solution Approach 2:
The patent performs preliminary organization of logical addresses and their corresponding physical page locations during the normal data writing process. The conversion table is continuously updated with this information as data is written, so when damage occurs, the pre-organized information can be quickly recovered without needing to scan entire blocks, thus reducing recovery time while ensuring reliability.
2Reliability
If sequence numbers are recorded together with data to identify the latest version, then data integrity can be maintained, but the device complexity increases
Solution Approach 1:
Instead of using complex global sequence numbers for the entire block, the patent applies a simple local quality marker (old/new information) at the page level within the conversion table entries. This localized approach maintains data integrity by allowing direct comparison of individual page versions without requiring complex global sequencing mechanisms, thereby reducing device complexity while preserving reliability.
3Reliability
If the conversion table is reestablished by reading all blocks, then complete data can be recovered, but the processing time and computational load increase significantly
Solution Approach 1:
The patent segments the conversion table management into individual page-level entries, each containing only the logical address and old/new marker information. This segmentation allows the system to process and recover information page by page rather than requiring simultaneous processing of entire blocks, thereby maintaining complete data recovery capability while significantly improving reestablishment efficiency through manageable, discrete units.
4Reliability
If old and new information is written into each page, then the chronological order can be determined for reestablishment, but the storage space requirement increases
Solution Approach 1:
The patent applies partial action by writing old/new information markers only in specific scenarios (when data is actually written to a page) rather than continuously or excessively. This selective application maintains chronological ordering accuracy by recording only the necessary version information while avoiding unnecessary storage consumption from redundant markers, thus balancing reliability with storage efficiency.
Data Source
AI summary
A storage device including a flash memory, and circuitry that manages a logical address and a physical address so as to be converted using a conversion table, writes a logical address and old and new information indicating a timing when the data is written, into the physical address together with the data, writes at least latest old and new information of the old and new information written in the block into a predetermined page of the block, and reestablishes the conversion table by arranging the logical address recorded in each page included in the block and the physical address corresponding to the logical address in association with each other, in chronological order of the latest old and new information read out from each block of the flash memory, at a predetermined reestablishment timing for performing reestablishment of the conversion table.