NVM Sector Mapping for Integrated Data and Metadata Storage
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Solution Overview
Problem
Non-volatile memories, particularly flash memories, face inefficiencies in storing data and metadata due to the need to erase entire sectors, leading to wasted physical space when data and metadata are stored separately, as partial sector erasure is not possible.
Innovation Solution
Storing data and corresponding metadata in the same sector, utilizing a memory access circuit to efficiently map logical addresses to physical addresses, with each sector size being an integer power of two and the number of data blocks following a (2 m< -1)*2 n< format, employing divide-by-(2 m< -1) and modulo-(2 m< -1) circuits for precise address calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If data and metadata are stored in separate sectors, then data management is simplified, but physical storage space is wasted due to inability to perform partial sector erasure
Solution Approach 1:
The patent combines data and metadata into the same sector, allowing them to be stored together in a unified structure. This merging enables partial sector erasure operations to affect only the necessary portions, reducing wasted physical space while maintaining efficient management through the integrated layout.
Solution Approach 2:
The sector is segmented into distinct regions: a data portion for storing user data and a metadata portion for storing associated metadata. This segmentation within the unified sector structure allows selective erasure and management of different components while preserving the overall efficiency benefits.
2Loss of substance
If sector size is increased to accommodate both data and metadata, then storage efficiency improves, but address mapping complexity increases
Solution Approach 1:
The patent defines specific parameter relationships: sector size is set to an integer power of two, and the number of data blocks per sector follows the form (2^m - 1) * 2^n. These parameter constraints simplify the address mapping mathematics while ensuring efficient storage utilization.
Solution Approach 2:
The patent introduces an intermediary mapping structure where logical block addresses are first mapped to sector addresses, and then to specific data block and metadata offsets within the sector. This multi-stage mapping approach breaks down the complexity into manageable steps.
3Speed
If separate sectors are used for data and metadata, then data access is faster, but storage capacity is reduced
Solution Approach 1:
By merging data and metadata in the same sector with defined portions, the system achieves both fast access (through unified sector operations) and maximum capacity utilization (through efficient space allocation). The integrated structure eliminates gaps between separate sectors while maintaining access efficiency.
Data Source
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AI summary
A memory device includes a Non-Volatile Memory (NVM) comprising a plurality of sectors, and a memory access circuit. The memory access circuit is configured to receive, from a host, a logical address of a block of data, to compute a mapping of the logical address to a data physical address comprising a selected sector among the plurality of sectors and a selected data offset within the same selected sector, to compute a metadata physical address that comprises the selected sector and a metadata offset in the selected sector, and to access the block of data at the data physical address, and the metadata at the metadata physical address.