Flash Memory Garbage Collection Block Reuse
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Solution Overview
Problem
Memory devices with MLC flash memory face instability issues during garbage collection, leading to incomplete operations due to sudden power-offs, which can cause the GC mechanism to fail and result in the rapid depletion of available blocks for data storage, especially with increasing block sizes and unstable power sources.
Innovation Solution
A method for reusing destination blocks in memory devices involves writing valid data and source information into data and spare regions during garbage collection, allowing for the resumption of data collection from source blocks after a power-off event, and using an empty-page search to find the last valid page in the destination block for continued data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the memory device performs garbage collection by collecting valid data from source blocks to destination blocks, then data management efficiency is improved, but sudden power-off events can interrupt the process causing incomplete data collection and GC mechanism failure
Solution Approach 1:
The patent applies preliminary action by recording source block information and valid data locations in the spare region before power-off events can occur. This allows the system to resume GC operations from the correct state after power restoration, preventing incomplete data collection and ensuring GC mechanism reliability while maintaining data management efficiency
Solution Approach 2:
The patent implements feedback by using the spare region to store source block information that provides state information about the GC process. This feedback mechanism allows the system to detect incomplete GC operations after power-off and automatically resume them, resolving the contradiction between productivity and reliability
2Reliability
If the memory device re-performs previous GC tasks after sudden power-off, then data integrity is maintained, but time consumption increases and performance deteriorates
Solution Approach 1:
The patent records the state of GC operations including source block information and valid data locations in the spare region before power-off. This preliminary recording allows the system to resume operations from the exact point of interruption rather than re-performing all tasks, maintaining data integrity while significantly reducing time loss
Solution Approach 2:
The system uses its own spare region storage capacity to automatically track and remember GC operation state, enabling self-resumption after power-off without external intervention. This self-service mechanism maintains data integrity while avoiding redundant time-consuming operations
3Quantity of substance
If the block size in the memory device increases to improve storage capacity, then recording density is improved, but the severity of power-off interruption problems increases and blank blocks deplete faster
Solution Approach 1:
The patent records source block information and valid data locations in the spare region before power-off events occur. This preliminary action is especially critical for large blocks where interruption causes more severe problems, allowing resumption without re-processing and preventing rapid depletion of blank blocks, thus maintaining GC stability while supporting large block sizes for high capacity
Solution Approach 2:
The spare region provides feedback information about the GC process state including source block locations and valid data positions. This feedback mechanism allows the system to track progress in large blocks and resume operations accurately after power-off, preventing the rapid depletion of blank blocks that occurs with larger block sizes
4Ease of manufacture
If the memory device uses MLC flash memory to reduce cost and increase capacity, then manufacturing cost is reduced and storage capacity is increased, but instability issues during GC operations occur
Solution Approach 1:
The patent records GC operation state including source block information and valid data locations in the spare region before power-off events. This preliminary recording compensates for MLC instability by ensuring accurate state tracking, allowing resumption without data loss or corruption, thus maintaining GC stability while benefiting from MLC cost and capacity advantages
Solution Approach 2:
The spare region provides feedback about the GC process state in MLC memory operations. This feedback mechanism allows the system to detect and recover from incomplete operations caused by MLC instability, maintaining GC reliability while preserving the cost and capacity benefits of MLC flash memory
Data Source
AI summary
A method for reusing a destination block related to garbage collection (GC) in a memory device, the associated memory device and the controller thereof, and the associated electronic device are provided. The method may include: when writing any page of a subset of a plurality of pages of the destination block in a GC procedure, writing valid data and source information into a data region and a spare region of the page, respectively, wherein a power-off event occurs during writing the destination block; after the power-off event ends, performing empty-page search in the destination block to find the last valid page within the destination block; and writing a set of subsequent valid data obtained from the source block into a subsequent page within the destination block, to reuse the destination block.