Flash Memory Block Replacement for Wear Management
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Solution Overview
Problem
Flash memory devices have limited lifespan due to their characteristics, such as inability to overwrite or update in-place, different read/write and erase units, and limited program/erase cycles, necessitating a method to extend their life by optimizing capacity usage.
Innovation Solution
A data storage apparatus with multiple planes, each divided into regions for system data and user data, where a controller manages the operation by moving system data copies from a source memory block to a replaceable region, effectively extending the lifespan by reallocating and replacing memory blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If flash memory apparatus is used for data storage, then storage capacity and price competitiveness are improved, but lifespan is limited due to limited program/erase cycles
Solution Approach 1:
The flash memory apparatus is divided into multiple planes, with each plane containing system data regions and user data regions. This segmentation allows independent management and wear distribution across planes, extending overall lifespan while maintaining storage capacity.
Solution Approach 2:
The patent implements a block replacement mechanism where worn-out memory blocks (victim blocks) are identified and replaced with fresh blocks from a pool. System data is relocated to healthy blocks, and the worn blocks are retired, thereby recovering storage functionality and extending device lifespan.
2Reliability
If system data is stored in dedicated memory blocks, then data integrity is improved, but storage efficiency deteriorates due to reduced available capacity
Solution Approach 1:
Memory blocks are designed to serve multiple functions: they can store system data, user data, or act as replacement blocks depending on their wear status. The block replacement pool dynamically assigns blocks to different roles, maximizing both data integrity and storage efficiency.
Solution Approach 2:
The patent implements dynamic block allocation where the roles of memory blocks (system data block, user data block, or replacement block) are not fixed but change based on wear levels and storage needs. This dynamic management ensures optimal data integrity while maximizing available capacity.
3Reliability
If copy of system data is maintained for redundancy, then reliability is improved, but storage capacity is reduced due to duplicate data occupation
Solution Approach 1:
Redundant copies of system data are strategically placed in replaceable blocks within the block replacement pool. When blocks wear out, the redundancy mechanism allows data to be relocated to fresh blocks, maintaining reliability while the worn blocks are recovered for replacement purposes.
Data Source
AI summary
A data storage apparatus may include a storage and a controller. The storage includes a plurality of planes each composed of a plurality of memory blocks, and is divided into a first region and a second region. An original of system data and a copy of the system data are stored in the first region. The controller is configured to perform a relief operation of moving the copy of the system data stored in a source memory block of the first region to a victim plane and switching the source memory block to a region replaceable with the second region.