Flash Memory Controller Zoned Namespace Mapping
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Solution Overview
Problem
The existing flash memory controllers face challenges in efficiently managing data writes to zoned namespaces in flash memory modules due to the need for large mapping tables between logical and physical addresses, leading to increased processing burdens and storage occupancy.
Innovation Solution
A flash memory controller that configures zoned namespaces with continuous logical addresses and uses specific access modes to write data across multiple blocks, optimizing the mapping table size by writing data sequentially and utilizing remaining pages for invalid data or keeping them blank, thereby reducing the size of the logical to physical address mapping table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flash memory controller creates detailed page-based mapping tables between logical addresses and physical addresses for zoned namespace data writes, then accurate address mapping is achieved, but the processing burden on the controller increases and SRAM/DRAM storage space is occupied
Solution Approach 1:
The patent segments the mapping table into two parts: a small zone-based mapping table stored in SRAM that maps logical zone addresses to physical block addresses, and a larger page-based mapping table stored in DRAM that maps logical page addresses to physical page addresses. This segmentation allows the controller to use the small SRAM table for zone-level operations while maintaining detailed page-level mapping capability when needed, thereby reducing the processing burden and SRAM occupancy while preserving address mapping accuracy.
2Measurement precision
If a flash memory controller creates detailed page-based mapping tables between logical addresses and physical addresses for zoned namespace data writes, then accurate address mapping is achieved, but SRAM and DRAM storage space is occupied
Solution Approach 1:
The patent segments the mapping table into two parts: a small zone-based mapping table stored in SRAM that maps logical zone addresses to physical block addresses, and a larger page-based mapping table stored in DRAM that maps logical page addresses to physical page addresses. This segmentation allows the controller to use the small SRAM table for zone-level operations while maintaining detailed page-level mapping capability when needed, thereby reducing the processing burden and SRAM occupancy while preserving address mapping accuracy.
3Adaptability or versatility
If the host device defines zone sizes that do not align with flash memory block sizes, then flexible namespace configuration is achieved, but the controller must create larger mapping tables to manage the mismatch
Solution Approach 1:
The patent segments the mapping table into two parts: a small zone-based mapping table stored in SRAM that maps logical zone addresses to physical block addresses, and a larger page-based mapping table stored in DRAM that maps logical page addresses to physical page addresses. This segmentation allows the controller to use the small SRAM table for zone-level operations while maintaining detailed page-level mapping capability when needed, thereby reducing the processing burden and SRAM occupancy while preserving address mapping accuracy.
Solution Approach 2:
The patent introduces an intermediary zone-based mapping layer that sits between the host's logical address space and the flash memory's physical address space. This zone-based mapping table acts as a mediator that translates logical zone addresses to physical block addresses, thereby reducing the complexity of the overall mapping process and allowing the controller to handle zone-size mismatches more efficiently.
Data Source
AI summary
The present invention provides a control method of a flash memory controller, wherein the flash memory controller is configured to access a flash memory module, and the control method includes the steps of: receiving a settling command from a host device to configure a portion space of the flash memory module as a zoned namespace; receiving a write command from the host device to write data corresponding a first zone into a plurality of blocks of the flash memory module, wherein an access mode chose by the flash memory controller is determined based on a size of each zone and a size of each block.