Cold Address Management for Nonvolatile Memory Wear Leveling
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Solution Overview
Problem
Conventional nonvolatile memory devices face reduced lifetime due to concentrated write operations, necessitating effective wear leveling that currently lacks efficient management of cold addresses, leading to suboptimal distribution of write operations across all cells.
Innovation Solution
A semiconductor device with a media controller, cold address manager, and region information storage that detects and manages cold addresses by updating a stack and region information at predetermined periods, ensuring write requests are distributed evenly across the memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wear leveling operations are performed by remapping logical addresses from hot addresses to cold addresses, then write operations are distributed across memory cells, but if the selected cold address has warm property, wear leveling operations are performed frequently reducing efficiency
Solution Approach 1:
The system performs preliminary detection of cold addresses with truly cold properties (not warm) before executing wear leveling operations. By pre-screening candidate addresses using the cold address detector and reference counter, the system avoids selecting warm addresses that would require frequent remapping, thus preventing inefficient wear leveling operations while ensuring reliable write distribution
Solution Approach 2:
The system implements feedback mechanisms where the cold address detector continuously monitors address access patterns and updates the reference counter accordingly. This feedback loop ensures that only addresses with consistently low write activity are selected as cold addresses, preventing the selection of warm addresses and improving wear leveling efficiency while maintaining memory reliability
2Ease of manufacture
If conventional wear leveling manages only hot addresses without special cold address management, then implementation is simple, but cold addresses are not efficiently utilized leading to suboptimal write distribution
Solution Approach 1:
The system segments address management into distinct components: hot address management for frequently written addresses and cold address management for infrequently written addresses. By dividing the address space and implementing separate detection and management mechanisms for cold addresses, the system achieves efficient write distribution while maintaining manageable complexity through modular architecture
Solution Approach 2:
The wear leveling system is enhanced to perform multiple functions: traditional hot address remapping and new cold address detection and management. The unified wear leveling controller can selectively apply remapping operations based on address characteristics, making the system more versatile and efficient without requiring completely separate management systems
Data Source
AI summary
A semiconductor device may include a media controller configured to output a write requested address when a write request to a nonvolatile memory device is provided from a host; and a cold address manager. The cold address manager may include a stack storing meta data for the write requested address, region information storage configured to manage addresses of the nonvolatile memory device with regions such that length of a region of the regions may vary after a predetermined period, a cold address detector configured to update the stack and the region information storage after the predetermined period and to detect whether an address of the nonvolatile memory device is a cold address, the cold address having write requests performed at less than a predetermined level.