NAND Flash Volume Management for Dynamic SLC/MLC Partitioning
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Solution Overview
Problem
Current non-volatile memory devices face challenges in dynamically managing both high and normal reliability data on a single device, leading to errors and inefficiencies due to fixed allocation of memory partitions and reliance on external file management systems.
Innovation Solution
A multi-level cell (MLC) NAND flash memory device with a volume management system that includes a meta-volume directory for centralized management of memory partitions, allowing dynamic reassignment of SLC and MLC regions based on need, and utilizing error correction codes to enhance data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed allocation of memory partitions is used, then device complexity is reduced, but adaptability and reliability for different data types deteriorate
Solution Approach 1:
The patent implements dynamic partition reassignment by allowing the memory controller to dynamically allocate and reassign memory partitions between SLC and MLC modes based on data reliability requirements. The system transitions from fixed static partitions to dynamic partitions that can be reallocated as needed, enabling adaptability while maintaining manageable complexity through centralized control.
Solution Approach 2:
The memory device achieves multi-functionality by enabling the same physical memory blocks to serve different purposes (SLC or MLC mode) based on data type requirements. The volume management system provides universal partition management that can handle both high-reliability and normal-reliability data using the same hardware resources, eliminating the need for separate dedicated partitions.
2Device complexity
If external file management systems are used, then device complexity is reduced, but loss of information and errors increase
Solution Approach 1:
The memory device implements self-service by incorporating an integrated volume management system and meta-volume directory directly within the device. The system automatically tracks memory block assignments, manages partition allocations, and maintains data integrity information without requiring external file management software, thereby reducing information loss and errors while maintaining acceptable complexity.
Solution Approach 2:
The meta-volume directory acts as an intermediary data structure that centrally stores and tracks information about memory block assignments and partition configurations. This intermediary mechanism enables the system to maintain accurate information about data locations and integrity status, preventing information loss without requiring complex external management systems.
3Device complexity
If SLC and MLC partitions are permanently assigned, then device complexity is reduced, but reliability for high reliability data deteriorates
Solution Approach 1:
The system transitions from permanent static partition assignment to dynamic partition assignment where memory blocks can be reassigned between SLC and MLC modes based on the reliability requirements of the data being stored. High reliability data can be dynamically allocated to SLC partitions when needed, while normal reliability data uses MLC partitions, optimizing reliability without requiring permanently assigned partitions.
4Reliability
If multiple memory devices are used for high and normal reliability data, then reliability is improved, but device complexity and volume increase
Solution Approach 1:
The patent merges the functionality of separate high-reliability and normal-reliability memory devices into a single integrated memory device. The volume management system consolidates SLC and MLC partitions within one device, allowing both high-reliability and normal-reliability data to be stored together with unified management, thereby reducing overall system complexity and volume while maintaining reliability through appropriate partition allocation.
Solution Approach 2:
The single memory device achieves multi-functionality by simultaneously supporting both SLC-based high-reliability storage and MLC-based normal-reliability storage. The device universally handles different data types with different reliability requirements using the same hardware platform, eliminating the need for multiple separate devices while maintaining the reliability benefits of SLC for critical data.
Data Source
AI summary
Embodiments for partitioning a non-volatile memory device is described. In one embodiment a memory system includes a first addressable range of memory blocks for storing different types of data. The memory system is partitioned to include a second addressable range of memory blocks capable of storing data indicating attributes of the first addressable range of memory blocks. The second addressable range of memory blocks may also be periodically updated such that the capacities of the first addressable range of memory blocks may be dynamically adjusted depending on application needs and changes to the non-volatile memory device over time. In some embodiments, one partition of a memory device may be configured for high reliability data storage while a second partition is configured for normal reliability storage.