Memory Controller Reserving Unused NVM Space for Safe Shutdown
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Solution Overview
Problem
Existing memory systems face challenges in ensuring safe shutdown of volatile memory during power-down events without data loss, particularly due to variable write performance of non-volatile memory devices like flash memory, which can lead to incomplete data transfer before power is exhausted.
Innovation Solution
A method and memory controller that reserve a predetermined amount of unused dedicated memory in non-volatile memory, disable garbage collection during shutdown, and utilize a supplemental power supply to ensure reliable data transfer from volatile memory to non-volatile memory, optimizing bandwidth for data preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-volatile memory is used for data storage during shutdown, then data preservation is improved, but write performance variability causes incomplete data transfer before power exhaustion
Solution Approach 1:
The system performs preliminary actions by detecting shutdown conditions early and initiating data transfer from volatile to non-volatile memory before power is completely lost. The controller monitors power supply status and proactively starts the data preservation process, ensuring critical data is saved while power levels are still sufficient.
Solution Approach 2:
The system changes operational parameters by adjusting write performance requirements based on available power levels. When shutdown is detected, the controller modifies write speed parameters and data prioritization to match the limited energy available, ensuring complete data transfer under constrained power conditions.
2Use of energy by moving object
If power supply is reduced during shutdown, then energy consumption is decreased, but data transfer from volatile to non-volatile memory becomes incomplete
Solution Approach 1:
The system performs preliminary data transfer operations before power supply is fully reduced or cut off. By detecting shutdown conditions in advance, the controller initiates data saving to non-volatile memory while sufficient power remains available, completing the transfer before energy levels become critically low.
Solution Approach 2:
The system implements feedback mechanisms by monitoring power supply status and transfer progress in real-time. The controller adjusts data transfer rates and prioritization based on feedback from power level sensors, dynamically optimizing the balance between energy consumption and data transfer completeness during shutdown.
3Ease of operation
If garbage collection is enabled during normal operation, then memory management is improved, but it interferes with data transfer during shutdown
Solution Approach 1:
The system dynamically adjusts garbage collection behavior based on operational state. During normal operation, garbage collection runs to maintain memory health. Upon detecting shutdown conditions, the controller dynamically suspends or prioritizes data transfer operations over garbage collection, ensuring reliable data preservation while maintaining good memory management practices during active use.
Data Source
AI summary
Various embodiments are related to non-volatile memories, systems, and methods of using such. Some such embodiments include a memory controller that is configured to reserve a predetermined amount of unused dedicated memory in the NVM and control the memory system to operate in a normal mode of operation in which it is configured to provide at least write access to the NVM, enable a garbage collection process for the NVM, and maintain in the NVM at least said amount of dedicated unused memory. Reserving the predetermined amount of unused dedicated memory in the NVM and controlling the memory system to operate in the normal mode of operation includes reserving at least one specific unused dedicated memory portion in the NVM and controlling the memory system such that during the normal mode of operation the host's write access to the dedicated memory portion is disabled.