Non-Volatile Memory Address Map Recovery via Scan Pointers
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Solution Overview
Problem
Data storage devices using non-volatile memory face challenges in rebuilding a valid address map after a power loss, as existing solutions fail to effectively manage and restore logical address information.
Innovation Solution
A data storage device with a non-volatile memory system that includes a closed and open memory block, where a scan pointer and map scan information are generated to rebuild the address map by reading logical address information stored in the non-volatile memory, allowing the device to recover from power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the data storage device uses non-volatile memory blocks without additional recovery mechanisms, then the device structure is simple, but the device cannot validly rebuild the address map after power loss
Solution Approach 1:
The patent applies preliminary action by pre-generating and storing map scan information (including scan pointers and logical address information) in the non-volatile memory before power loss occurs. This pre-prepared information enables the controller to quickly rebuild the address map after power recovery without needing complex external recovery procedures, thus improving reliability while controlling complexity.
Solution Approach 2:
The patent introduces map scan information as an intermediary data structure that mediates between the physical memory blocks and the address map. This intermediary contains scan pointers and logical address information that facilitate the recovery process, allowing the system to rebuild the address map efficiently without direct complex interactions between all memory components.
2Loss of information
If the device stores complete address map information in volatile memory for quick access, then address translation is fast, but the information is lost during power loss
Solution Approach 1:
The patent pre-generates map scan information containing logical address information and stores it in non-volatile memory before power loss. This preliminary action ensures that the information is preserved across power cycles, preventing data loss while enabling quick recovery by simply reading the pre-stored scan information rather than rebuilding the entire address map from scratch.
Solution Approach 2:
The patent creates a copy of the essential address map information (logical address information and scan pointers) and stores it in non-volatile memory in the form of map scan information. This copy serves as a backup that can be quickly restored after power loss, minimizing information loss and reducing recovery time compared to reconstructing the entire address map.
3Reliability
If the controller reads all logical address information from the entire memory device after power loss, then the address map can be completely rebuilt, but the recovery process is time-consuming
Solution Approach 1:
The patent extracts only the essential information needed for address map recovery (logical address information and scan pointers) and stores it separately as map scan information in non-volatile memory. After power loss, the controller reads only this extracted critical information rather than scanning the entire memory device, which significantly reduces recovery time while ensuring address map validity.
Solution Approach 2:
The patent performs preliminary organization of logical address information into map scan information with scan pointers before power loss occurs. This pre-organized structure enables the controller to quickly locate and read only the necessary information after power recovery, rather than performing a time-consuming comprehensive scan of all memory blocks, thus reducing recovery time while maintaining reliability.
Data Source
AI summary
In a method of operating a data storage device including a non-volatile memory device, which includes a closed memory block and an open memory block, a scan pointer and a map scan information of the open memory block is generated. The scan pointer indicates a page next to a page to which a writing operation is completed. The map scan information includes a logical address information mapped in a page of the open memory block. When the data storage device is recovered from a power loss, the logical address information is read based on the map scan information. An address map is rebuilt based on the read logic address information.