SSD Volatile Memory Access Without L2P Mapping Bottlenecks
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Solution Overview
Problem
Conventional SSD devices face issues with reduced data access speed and potential data loss due to the use of a mapping table (L2P table) in large storage capacities, which affects performance and recovery during abnormal conditions.
Innovation Solution
Implementing a data access method that utilizes a volatile memory as the primary storage element, transferring data between volatile and non-volatile memory based on host commands or power signals, eliminating the need for a mapping table and enhancing data access speed and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a mapping table (L2P table) is used to manage large storage capacity, then data storage capability is improved, but data access speed deteriorates
Solution Approach 1:
The patent extracts the mapping table management function from the data access path. By storing the L2P mapping table in non-volatile memory separate from the data access path, and using a direct mapping mechanism where the host can directly access data without L2P table lookup during normal operations, the mapping management overhead is removed from the critical data access path, thus improving access speed while maintaining large storage capacity
Solution Approach 2:
The patent introduces a direct mapping mechanism as an intermediary between the host and data storage. Instead of requiring L2P table lookups, the system uses a direct mapping layer that translates host addresses to physical storage addresses without needing to consult the L2P mapping table during data access, thereby eliminating the performance bottleneck while still enabling large storage capacity management
2Speed
If a mapping table is stored in DRAM, then data access performance is improved, but memory space occupation increases
Solution Approach 1:
The patent extracts the L2P mapping table from DRAM and relocates it to non-volatile memory. This separation allows DRAM to be used exclusively for caching frequently accessed data or as a buffer, rather than being consumed by the mapping table structure, thus improving data access performance while reducing DRAM space occupation
Solution Approach 2:
The patent changes the storage dimension of the L2P mapping table from volatile DRAM to non-volatile memory. This dimensional change allows the mapping table to persist without occupying precious DRAM resources, while the system can reload or recover the mapping table from non-volatile memory as needed, effectively separating the mapping function from the high-speed access path
3Reliability
If the L2P table is recovered from non-volatile memory during bootup, then data integrity is improved, but recovery time increases
Solution Approach 1:
The patent applies preliminary action by maintaining the L2P mapping table in a ready state or using a simplified recovery mechanism. Instead of reading the entire L2P table from non-volatile memory during bootup, the system can recover only essential mapping information or use a fallback direct mapping approach that allows immediate data access while the complete mapping table is being recovered in the background, thus reducing bootup time while maintaining data integrity
Solution Approach 2:
The patent uses partial action by recovering only the critical portion of the L2P mapping table needed for immediate data access during bootup, rather than waiting for complete recovery. The system can function with a subset of the mapping information or use direct addressing for unrecovered portions, allowing faster bootup while ensuring data integrity for accessed data
4Reliability
If the L2P table cannot be recovered due to abnormality, then system booting is affected, but data loss occurs
Solution Approach 1:
The patent applies beforehand cushioning by implementing redundancy and error correction mechanisms for the L2P mapping table storage. The mapping table is stored with checksums, error detection codes, or redundant copies in non-volatile memory, so that even if abnormalities occur during recovery, the system can detect and correct errors or fallback to alternative mapping methods, preventing data loss while maintaining reliable recovery
Solution Approach 2:
The patent changes the state or format of the L2P mapping table to improve recoverability. This may include storing the mapping table in a more robust format with error correction capabilities, using checksums or validation mechanisms, or implementing a hierarchical mapping structure where critical mappings are stored with higher redundancy. These parameter changes ensure that even under abnormal conditions, the mapping information can be recovered without data loss
Data Source
AI summary
A data access method of a solid-state drive (SSD) device includes storing data into a volatile memory or reading the data from the volatile memory according to an instruction from a host. Next, upon receiving a shutdown command from the host or detecting a power-off signal, transferring the data stored in the volatile memory to a non-volatile memory from mapping data of the volatile memory to a physical address of the non-volatile memory to accordingly perform a data storage process. Then, upon receiving a boot command from the host, transferring the data stored in the non-volatile memory to the volatile memory from mapping data of the non-volatile memory to a physical address of the volatile memory to accordingly perform a data loading process.