H2F Mapping Read-Mode Switching for Faster NAND Flash Reads
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Solution Overview
Problem
NAND flash devices face inefficiencies in executing host read commands due to the need for serial access and the inability to directly access random addresses, leading to wasted time and computing resources when incorrect read modes are employed.
Innovation Solution
A method and apparatus that utilize a processing unit to determine the usage state of mapping records in a RAM based on past hits, switching between group-mapping and section-mapping read modes to optimize the reading of host read commands, thereby reducing resource waste and improving execution efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If group-mapping read mode is used to read multiple records from H2F table, then data retrieval speed is improved, but memory usage increases when accumulation threshold is exceeded
Solution Approach 1:
The system dynamically switches between group-mapping read mode and section-mapping read mode based on the accumulation threshold. When the number of mapping records in RAM exceeds the threshold, the system transitions from group-mapping mode (which reads multiple records) to section-mapping mode (which reads fewer records), thereby adapting memory usage to current operational needs while maintaining optimal data retrieval speed.
Solution Approach 2:
The invention changes the operational parameter (read mode) based on the accumulation threshold. By monitoring the number of mapping records and comparing it against the threshold, the system adjusts the read operation parameters to either read multiple records (group-mapping mode) or fewer records (section-mapping mode), optimizing the balance between speed and memory usage.
2Quantity of substance
If section-mapping read mode is used to read only first records from H2F table, then memory usage is reduced, but data retrieval speed decreases
Solution Approach 1:
The system dynamically adjusts the read mode based on current memory conditions. When the number of mapping records in RAM is below the accumulation threshold, the system uses section-mapping read mode to minimize memory usage. This dynamic adaptation ensures that memory consumption is optimized without permanently sacrificing data retrieval speed, as the system can switch to group-mapping mode when speed becomes the priority.
3Device complexity
If incorrect read modes are employed in NAND flash devices, then device complexity is reduced, but execution efficiency deteriorates due to wasted time and computing resources
Solution Approach 1:
The system implements feedback by monitoring the number of mapping records in RAM and comparing it against the accumulation threshold. Based on this feedback, the system automatically selects the appropriate read mode (group-mapping or section-mapping), ensuring that execution efficiency is optimized without requiring complex manual intervention or overly complicated device architecture.
Data Source
AI summary
The invention is related to a method, performed by a processing unit, includes: obtaining a group number and a section number associated with a logical address carried in a host read command; determining whether a variable corresponding to a first mode is lower than or equal to an accumulation threshold; performing operations of the first mode for reading first records associated with the group number and the section number from a host-address to flash-address mapping (H2F) table in a flash module, and second records being located after the first records, and storing them in a random access memory (RAM) when the variable is lower than or equal to the accumulation threshold; performing operations of a second mode for reading the first records from the H2F table in the flash module only, and storing them in the RAM when the variable is higher than the accumulation threshold.