Runtime Exclusive-Or Zoning for Data Folding Error Recovery
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Solution Overview
Problem
Data storage devices face challenges in ensuring accurate data transfer during the 'folding' process from single-level cell (SLC) blocks to multi-level cell (MLC) blocks, particularly due to errors in programming wordlines, which can lead to data loss and integrity issues, especially in defective memory materials where adjacent wordlines may be affected.
Innovation Solution
The implementation of runtime exclusive-or zoning in data storage devices, where the controller dynamically forms zones during enhanced post-write-read (EPWR) operations, pauses the folding process to reprogram data from failing wordlines into a new SLC block, and recalculates parity to maintain data integrity and prevent full zone commit failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the folding operation continues without pausing to handle errors, then productivity is maintained, but data integrity deteriorates due to potential data loss from programming errors
Solution Approach 1:
The patent implements preliminary error detection by performing enhanced post-write-read (EPWR) operations immediately after programming data into MLC blocks, before the folding operation continues. This allows errors to be identified early, and corrective actions to be taken before additional data processing occurs, thus maintaining data integrity while minimizing disruption to overall productivity
Solution Approach 2:
The patent introduces a buffer or intermediate storage mechanism that temporarily holds data during the folding operation. When errors are detected, the system can pause the folding operation, reprogram failing wordlines into alternative SLC blocks, and resume without losing progress, thus maintaining both data integrity and productivity
2Reliability
If the folding operation is paused to reprogram failing wordlines, then data integrity is improved, but loss of time increases due to operation interruption
Solution Approach 1:
The patent segments the folding operation into smaller units that can be independently managed. When errors are detected in specific wordlines, only those particular segments need to be paused and reprogrammed, while other segments can continue processing. This granular approach minimizes the overall time loss while ensuring data integrity for the affected segments
Solution Approach 2:
The patent implements a mechanism to discard failed programming attempts and recover by reprogramming the same data into alternative SLC blocks. The system maintains a record of successful data placements and can quickly recover from failures without reprocessing entire data sets, thus reducing time loss while maintaining data integrity
3Reliability
If additional parity protection is implemented for failing wordlines, then reliability is improved, but device complexity increases due to additional parity calculation and storage requirements
Solution Approach 1:
The patent merges the parity protection mechanism with the existing folding operation framework. Instead of implementing a separate complex error handling system, the patent integrates parity calculation and verification into the standard folding process, allowing additional parity protection to be provided while reusing existing computational resources and data structures
Solution Approach 2:
The patent implements a universal error handling mechanism that serves multiple functions: it detects programming errors, manages reprogramming of failing wordlines, provides additional parity protection, and maintains data integrity across different folding scenarios. This multi-functional approach reduces overall system complexity by consolidating error handling capabilities into a single versatile framework
Data Source
AI summary
A data storage device initially stores incoming data from a host in single-level cell (SLC) blocks and later folds the data from those blocks into a multi-level cell (MLC) block. If an error is detected during the folding operation, the data storage device pauses the folding operation, programs data that failed to be program and other data from the initial SLC blocks into another SLC block, and then resumes the folding operation. This can be part of a dynamic runtime zoning process where the data storage device determines a set of wordlines that will fall under one zone at runtime during an enhanced post-write-read (EPWR) operation.