Memory Controller L2P Table Management for Flash Stability
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Solution Overview
Problem
Existing memory devices face challenges in ensuring robust data access and stability, particularly in MLC flash memories, due to insufficient RAM storage capacity and potential side effects from existing management mechanisms, which can lead to operational issues and security concerns.
Innovation Solution
A method for performing access management in memory devices that involves receiving host commands and logical addresses, checking for equivalence in L2P-table indices, and loading the logical-to-physical table from non-volatile memory to RAM for accurate data access, ensuring correct data retrieval and security without introducing side effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MLC flash memory is used to increase storage capacity and reduce cost, then storage density is improved, but data stability and access reliability deteriorate
Solution Approach 1:
The patent introduces a controller as an intermediary between the host and MLC flash memory. The controller implements sophisticated access management mechanisms including wear leveling, bad block management, and error correction to mediate the inherent instability of MLC memory cells, thereby maintaining data reliability while utilizing high-density storage
Solution Approach 2:
The patent changes operational parameters such as programming voltage, read voltage, and erase voltage to optimize the balance between storage capacity and data stability. By dynamically adjusting these parameters based on memory cell state and usage patterns, the system maintains reliable data access while maximizing the utilization of MLC's multi-level storage capability
2Quantity of substance
If RAM size is reduced to control budget, then cost is improved, but data access robustness and security deteriorate
Solution Approach 1:
The patent segments the address mapping functionality by implementing a divided page table structure where the page table is stored in non-volatile memory rather than requiring full residency in RAM. This segmentation allows the system to maintain robust data access capabilities while using minimal RAM for only the actively accessed portions of the address space
Solution Approach 2:
The patent performs preliminary actions by pre-loading only the necessary portions of the page table into RAM based on predicted access patterns and current operational needs. This allows the system to maintain security and robustness for anticipated operations while minimizing RAM usage for unexpected or less critical data access scenarios
3Productivity
If L2P table is always loaded to RAM for fast access, then data access speed is improved, but RAM memory usage increases
Solution Approach 1:
The patent implements a dynamic page table management system where the L2P table residency in RAM is not fixed but adapts based on access frequency, memory pressure, and operational context. Frequently accessed mappings remain in RAM for fast access, while less frequently accessed mappings are kept in non-volatile memory and loaded on-demand, creating a dynamic balance between access speed and memory usage
Data Source
AI summary
A method for performing access management in a memory device, the associated memory device and the controller thereof, and the associated electronic device are provided. The method may include: receiving a host command and a logical address from a host device; performing at least one checking operation to obtain at least one checking result, for determining whether to load a logical-to-physical (L2P) table from the NV memory to a random access memory (RAM) of the memory device, wherein the L2P table includes address mapping information for accessing the target data, and performing the at least one checking operation to obtain at least one checking result includes checking whether a first L2P-table index pointing toward the L2P table and a second L2P-table index sent from the host device are equivalent to each other; and reading the target data from the NV memory, and sending the target data to the host device.