Flash Translation Layer Resetting in Data Storage Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data storage devices face issues with malfunction-induced stuck states due to bit flips or NAND uncorrectable ECC errors, leading to loss of data and inability to access stored information, as repeated initialization attempts fail to address the underlying cause and preserve the flash translation layer (FTL) state.
Innovation Solution
A data storage device with a controller that monitors malfunctions, increments an assert count, and performs a flash translation layer (FTL) resetting operation in read-dedicated mode when the assert count exceeds a reference value, skipping operations like dummy writes and garbage collection to prevent further errors during initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated initialization attempts are made to fix malfunction, then the storage device may be reset, but the FTL state information is lost and data access becomes impossible
Solution Approach 1:
The controller performs a simplified FTL resetting operation before the full initialization process when malfunction is detected. This preliminary action preserves critical FTL state information while still resetting the storage device, preventing complete loss of initialization history and enabling subsequent data access.
2Ease of operation
If normal FTL resetting operation is performed during initialization, then the storage device can be reset, but dummy writes and garbage collection operations may cause further malfunctions
Solution Approach 1:
The controller extracts and performs only the essential FTL resetting operations while skipping unnecessary operations such as dummy writes and garbage collection. This selective approach maintains the core functionality of resetting the FTL without introducing additional malfunctions that would occur during complete initialization.
Solution Approach 2:
The controller performs a partial FTL resetting operation that includes only the necessary steps for initialization, omitting optional operations like dummy writes and garbage collection. This partial action is sufficient to reset the FTL and enable data access while avoiding the additional risk of malfunctions from complete initialization.
3Reliability
If complete initialization is performed to fix malfunction, then the storage device can be reset, but the initialization process is time-consuming and may fail repeatedly
Solution Approach 1:
The controller performs a partial FTL resetting operation that achieves the necessary reset functionality without executing the complete initialization sequence. This partial action significantly reduces initialization time while maintaining sufficient reliability to fix the malfunction and enable data access.
Data Source
AI summary
A data storage device may include a nonvolatile memory device, and a controller configured to increase an assert count, when a malfunction occurs while an operation for a command received from a host device is executed, the assert count representing the number of times the malfunction has occurred, and execute a flash translation layer (FTL) resetting operation in a read-dedicated mode in response to an initialization request from the host device when the assert count is greater than or equal to a reference value.