Flash Controller Deterioration Table for All-Zero Data
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Solution Overview
Problem
Flash memory storage devices face issues with data deterioration due to all-0's or all-1's data, which can damage storage capabilities and lead to repeated duplication of undesirable data, causing storage space utilization problems.
Innovation Solution
A data storage device with a controller that updates a deterioration table to record deteriorated logical addresses, invalidates target data without moving it during garbage collection, and performs safety moving by copying high-risk blocks to safe blocks after modifying the data to prevent duplication of all-1's or all-0's data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all-0's or all-1's data is stored in flash memory, then data can be written to the memory, but the storage capability deteriorates and undesirable data is repeatedly duplicated
Solution Approach 1:
The controller performs preliminary detection of all-0's or all-1's data before storage and takes preventive action by invalidating such data in the deterioration table, preventing the harmful effect of data deterioration before it occurs
Solution Approach 2:
The controller converts the harmful all-0's or all-1's data into a useful indicator by using it to update the deterioration table, transforming the harmful factor into a mechanism for preventing future data deterioration
2Productivity
If garbage collection moves all data from source block to destination block, then storage space is reclaimed, but deteriorated data is duplicated consuming additional storage space
Solution Approach 1:
The controller extracts and identifies deteriorated data (all-0's or all-1's) from the source block during garbage collection and excludes it from being moved to the destination block, preventing unnecessary duplication
Solution Approach 2:
The controller uses the deterioration table as feedback information to identify which data in the source block should not be moved during garbage collection, optimizing storage space utilization by avoiding duplication of deteriorated data
3Reliability
If safety moving copies high-risk blocks to safe blocks, then data is protected from deterioration, but storage operations increase
Solution Approach 1:
The controller applies different treatment to different data: all-0's or all-1's data is invalidated and not moved, while other valid data is moved normally, optimizing the safety moving process by avoiding unnecessary operations on deteriorated data
Data Source
AI summary
A solution for deteriorated non-volatile memory is shown. When determining that raw data read from the non-volatile memory is undesirable data, the controller updates a deterioration table to record a deteriorated logical address of the raw data that is the undesirable data. When performing garbage collection from a source block associated with the deteriorated logical address to a destination block and determining that the deteriorated logical address is listed in the deterioration table, the controller invalidates target data stored in the source block and mapped to the deteriorated logical address, without moving the target data from the source block to the destination block in the garbage collection.