Nonvolatile Memory Refresh Scanning for Block Reliability
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Solution Overview
Problem
Existing data storage devices using nonvolatile memory face performance degradation due to inadequate refresh operations, leading to reliability issues and reduced operational efficiency.
Innovation Solution
Implementing a data storage device with a nonvolatile memory system that performs proactive refresh operations, including both host-initiated and controller-managed scans, to identify and address memory block conditions, thereby enhancing reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional refresh operations are performed only on host request, then device complexity is reduced, but reliability deteriorates due to performance degradation
Solution Approach 1:
The controller performs a refresh scan operation proactively to identify memory blocks requiring refresh before the host requests it. This preliminary detection allows the system to anticipate refresh needs and execute refresh operations timely, preventing performance degradation and ensuring reliability without requiring the host to continuously monitor memory status.
Solution Approach 2:
The refresh scan operation provides feedback information about the status of memory blocks to the controller. Based on this feedback, the controller intelligently determines which memory blocks require refresh operations and schedules them appropriately, creating a closed-loop control system that adapts to actual memory conditions rather than following a fixed refresh schedule.
2Reliability
If proactive refresh scan operations are implemented, then reliability is improved, but loss of time increases due to additional operations
Solution Approach 1:
Instead of performing refresh operations on all memory blocks, the refresh scan operation identifies only those specific memory blocks that require refresh. This partial action approach applies refresh operations selectively to affected blocks rather than universally, reducing the total time consumed while maintaining reliability.
Solution Approach 2:
The refresh scan operation quickly assesses memory block status and skips memory blocks that do not require refresh, focusing computational resources only on blocks with detected issues. This allows the system to rapidly identify and address problematic blocks without wasting time on healthy memory regions.
3Productivity
If refresh operations are delayed until host request, then power consumption is reduced, but productivity deteriorates due to performance degradation
Solution Approach 1:
The system performs a preliminary refresh scan to detect memory blocks needing refresh before productivity-critical operations are affected. By anticipating refresh needs in advance, the system can schedule refresh operations during low-activity periods, ensuring optimal performance when the host requires data access while minimizing power consumption during high-activity periods.
Solution Approach 2:
The refresh operation timing and frequency are dynamically adjusted based on detected memory conditions and current system activity levels. When memory issues are detected, the system increases refresh activity; when memory is healthy, it reduces refresh frequency, creating a dynamic balance between productivity and power consumption rather than using a static refresh schedule.
Data Source
AI summary
A storage device comprising: a nonvolatile memory device including a plurality of memory blocks; and a device controller configured to control the nonvolatile memory device to determine a memory block to perform a refresh operation and to control the memory block to perform the refresh operation to recover data of the memory block.