Auto-increment Write Count for Nonvolatile Memory Arrays
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Solution Overview
Problem
Nonvolatile memory devices face challenges with limited write endurance and write disturb issues, which require efficient tracking of write counts to manage cell endurance and data integrity.
Innovation Solution
The system employs a selected NV memory array to store and auto-increment the write count metadata, eliminating the need for the controller to read and increment the write count, thereby saving a read cycle for each write cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the controller reads and increments the write count for each write operation, then the write count tracking is accurate, but the write bandwidth efficiency deteriorates due to the additional read cycle
Solution Approach 1:
The patent implements a write count counter circuit integrated within the media controller that automatically increments the write count for each write operation without requiring the controller to read the current count from nonvolatile media. This self-service mechanism eliminates the read cycle overhead while maintaining accurate write count tracking, directly resolving the technical contradiction between measurement precision and productivity.
2Stability of the object's composition
If the write count is stored in nonvolatile media, then the write count persists across power cycles, but the operational complexity increases due to the need for read-modify-write operations
Solution Approach 1:
The patent segments the write count storage function by maintaining the count in a dedicated counter circuit within the media controller rather than storing it in nonvolatile media. This segmentation allows the write count to persist across power cycles through the counter's internal state while eliminating the complex read-modify-write operations, as the counter automatically increments on each write operation.
Solution Approach 2:
The patent introduces an intermediary counter circuit as a mediator between the write operation and the nonvolatile media. This counter automatically tracks write operations and can trigger refresh operations when thresholds are reached, eliminating the need for the controller to directly read and modify write count values in nonvolatile media, thus reducing operational overhead while maintaining persistence.
3Measurement precision
If the system performs read operations to increment write count, then the write count is accurately updated, but the time required for write operations increases
Solution Approach 1:
The patent implements preliminary action by having the counter circuit ready to automatically increment the write count at the moment of each write operation, without requiring prior read operations. The counter is pre-configured to track write operations and can immediately update the count, eliminating the time-consuming read-modify-write sequence and reducing the time required for write operations while maintaining accurate updating.
Data Source
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AI summary
A memory device has multiple nonvolatile (NV) memory arrays that collectively store a block of data, with each array to store a portion of the data block. A selected NV memory array stores a write count for the block of data. In response to a write command, the NV memory arrays that store data perform an internal pre-write read. The selected NV memory array that stores the write count will perform a pre-write read of the write count, increment the write count internally to the selected NV memory array, and write the incremented write count back to the selected NV memory array.