Storage Device Memory Segmentation for Selective Refresh

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Solution Overview

Problem

Semiconductor memories face issues with power consumption due to refresh operations and data deterioration, leading to unrecoverable memory errors, especially in volatile DRAMs.

Innovation Solution

A storage device with a main memory divided into segments where refresh operations are enabled in some segments and disabled in others, using a cache memory to store metadata and a memory controller to manage data movement based on cache hits and misses, reducing power consumption by disabling refresh on masked segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refresh operation is enabled in all memory segments, then data reliability is maintained, but power consumption increases

Engineering Contradiction:

Improvedata reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The memory device is divided into multiple segments (first segment group and second segment group), allowing selective refresh operations. The first segment group undergoes refresh operations to maintain data reliability, while the second segment group is masked to disable refresh operations, reducing power consumption. This segmentation enables differential power management across memory regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different refresh policies are applied to different memory segments based on their usage patterns. The first segment group (containing metadata to be cache hit) receives refresh operations to ensure data integrity, while the second segment group (containing metadata to be cache miss or dirty metadata) has refresh operations disabled to save power. This local differentiation optimizes both reliability and power consumption.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If refresh operation is disabled in memory segments, then power consumption is reduced, but data deterioration occurs leading to unrecoverable memory errors

Engineering Contradiction:

Improvepower consumptionVSAvoiddata reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system performs preliminary actions by copying metadata from the first segment group to the second segment group before disabling refresh operations in the second segment. This preliminary copying ensures that data is preserved in a safe location before the refresh operation is masked, preventing data deterioration even when refresh is disabled.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Metadata is copied from the first segment group (where refresh is enabled) to the second segment group (where refresh is disabled). This copying mechanism ensures that data integrity is maintained in the second segment group without requiring continuous refresh operations, thus reducing power consumption while preventing data deterioration.

Inventive Principle:

Principle #26Copying

3Use of energy by moving object

If metadata is stored in masked segment group, then power consumption is reduced, but data access complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddata access complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

A remap table is introduced as an intermediary data structure to manage the mapping between logical addresses and physical segment locations. The remap table stores mapping information that enables the memory controller to efficiently locate and access metadata in either the first or second segment group, thereby managing the complexity of data access in masked segments without significant performance degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If dirty metadata is copied to first segment group, then data reliability is ensured, but memory operation overhead increases

Engineering Contradiction:

Improvedata reliabilityVSAvoidmemory operation overhead

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs periodic flushing operations where dirty metadata is copied from the second segment group back to the first segment group at scheduled intervals or under specific conditions (e.g., before power-down, cache miss events). This periodic action ensures data reliability is maintained while minimizing the frequency of copy operations to reduce memory operation overhead and time loss.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12461857B2Storage device, operating method thereof, and electronic device

Publication Date: 2025.11.04 SAMSUNG ELECTRONICS CO LTD

AI summary

A storage device, an operation method thereof, and an electronic device are disclosed. A storage device includes a main memory comprising a first segment that is not masked and a second segment that is masked, a cache memory configured to store some metadata stored in the main memory, and a memory controller configured to map a physical address of the second segment to a physical address of the first segment in a remap table for dirty metadata to be stored in the second segment in response to a cache miss occurring.