SSD Read Voltage Lookup Table for Error Recovery
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Solution Overview
Problem
Current error processing in solid state disks is inefficient due to the sequential trial of read voltages from a retry table, leading to increased time consumption and reduced data read efficiency.
Innovation Solution
A method that determines a first read voltage based on the data storage time interval and performs reread error correction, with a second read voltage determined based on the storage time interval and number of data reads if the initial correction fails, until a preset accuracy condition is met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential trial of read voltages from retry table is used for error correction, then error correction can be performed, but time consumption increases and data read efficiency decreases
Solution Approach 1:
The patent pre-calculates and stores optimal read voltage values in a lookup table based on data storage time intervals before actual data reading operations. When a read error occurs, the system directly queries the pre-computed voltage from the lookup table according to the data's storage time, avoiding sequential trial of all voltages in the retry table. This preliminary preparation significantly reduces the time required for error correction while maintaining effective error correction capability.
Solution Approach 2:
The patent divides the error correction process into different stages based on data storage time intervals, assigning different read voltage strategies to different time periods. Instead of using a uniform sequential search approach for all data, the system applies locally optimized voltage selection for specific time intervals, thereby improving error correction efficiency for each particular storage duration while reducing overall time consumption.
2Reliability
If large number of read voltages are included in retry table, then error correction coverage is improved, but ERF time consumption increases
Solution Approach 1:
The patent extracts only the necessary read voltage values from the complete retry table and stores them in a compact lookup table organized by data storage time intervals. Instead of maintaining and searching through the entire large retry table during error correction, the system extracts and pre-organizes only the relevant voltage values needed for different time periods, reducing the search space and improving data read efficiency while preserving adequate error correction coverage.
Solution Approach 2:
The patent segments the error correction process by dividing data storage time into multiple intervals, with each interval having its own optimized read voltage values stored in the lookup table. This segmentation allows the system to handle different time-based error patterns separately, reducing the number of voltages that need to be tried for each specific case while maintaining comprehensive error correction coverage across all storage durations.
Data Source
AI summary
A solid state disk access method includes: determining, in response to a read error, a first read voltage of the current data block according to a current data storage time interval to which a data storage time of the current data block belongs; performing reread error correction on the data in the current data block based on the first read voltage; determining, if reread error correction of the current data block fails, a second read voltage corresponding to the current data block according to the current data storage time interval and a preset data read rule that is determined based on the data storage time interval and the number of data reads; and performing reread error correction on the data in the current data block based on the second read voltage until the reread error correction of the current data block meets a preset reread error correction condition.