Flash Translation Layer Table Rebuilding via Superblock Scanning
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Solution Overview
Problem
Conventional solid state drives face inefficiencies in scanning superblocks due to the time-consuming process of reading contents from all physical pages of the last superpage, especially when dealing with a large number of superblocks, which can lead to prolonged scanning times and potential data loss during power failures.
Innovation Solution
A superblock scanning method that reads only the first and last physical pages of the last superpage to determine the status of the superblock, significantly reducing the time required to scan each superblock and enabling faster rebuilding of the FTL table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all physical pages of the last superpage are read to determine superblock status, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent extracts only the essential information needed to determine superblock status by reading only the first and last physical pages of the last superpage, rather than reading all physical pages. This extraction principle reduces the scanning workload while maintaining sufficient accuracy for status determination.
Solution Approach 2:
The patent applies partial action by reading only a subset (first and last pages) of the complete set of physical pages in the last superpage. This partial reading provides enough information to determine superblock status without the excessive time cost of reading all pages, achieving a balance between precision and efficiency.
2Productivity
If the number of superblocks increases to enhance storage capability, then productivity is improved, but loss of time increases
Solution Approach 1:
The patent segments the information retrieval process by focusing only on critical pages (first and last of last superpage) rather than processing all pages across all superblocks. This segmentation approach allows the system to handle a large number of superblocks efficiently, as the time required per superblock is dramatically reduced.
Solution Approach 2:
The patent uses partial action to read only essential pages instead of all pages in each superblock. This reduces the time complexity from O(n) to O(1) per superblock, enabling the system to scale to handle increased numbers of superblocks without proportionally increasing the FTL table rebuilding time.
3Reliability
If conventional scanning method is used, then reliability is maintained, but loss of time increases
Solution Approach 1:
The patent extracts only the critical information needed for reliable superblock status determination (first and last pages of last superpage), eliminating the need to read all pages. This maintains the reliability of status detection while dramatically reducing the recovery time after power failures or system crashes.
Data Source
AI summary
A method is provided for rebuilding a flash translation layer table of a solid state drive. The superblock includes plural superpages. Each of the plural superpages includes plural physical pages. The method includes steps of confirming if the flash translation layer table is lost or not after the solid state drive is powered on; if the flash translation layer table is lost, starting a superblock scanning method for determining a status of the superblock; and rebuilding the flash translation table according to the status of the superblock. The superblock scanning method includes steps of reading contents of a first physical page and a last physical page of a last superpage in the superblock, and determining a status of the superblock according to the contents of the first physical page and the last physical page.