Nonvolatile Memory Block Erase Segmentation for Write Amplification

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Solution Overview

Problem

Nonvolatile memory with block erase characteristics, such as flash memory, faces challenges like write amplification, garbage collection inefficiencies, and increased complexity due to block-erase operations, which affect the longevity and efficiency of data storage systems.

Innovation Solution

Implementing a data storage scheme that utilizes linked lists of nonvolatile memory blocks with a FIFO structure, where data is marked for erasure based on reading, reducing the need for logical-to-physical address translations and optimizing garbage collection through a Write Once Read Once (WORO) technique, and prefetching data to volatile memory for low latency access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional block erase operations are used in nonvolatile memory, then data storage capacity is maintained, but write amplification increases and garbage collection efficiency deteriorates

Engineering Contradiction:
Improvewrite efficiencyVSAvoidwrite amplification
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The memory system segments the block erase operation into individual page-level operations. Instead of erasing entire blocks when garbage collection is needed, the system identifies and erases only the specific pages containing invalid data, significantly reducing the amount of data that must be moved during garbage collection and thereby reducing write amplification.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by maintaining a mapping structure that tracks the validity of data pages before garbage collection is needed. This allows the system to identify invalid pages in advance and prepare for selective erasure, avoiding the need to read and evaluate entire blocks during garbage collection operations.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If traditional block erase operations are used in nonvolatile memory, then data storage capacity is maintained, but garbage collection efficiency deteriorates

Engineering Contradiction:
Improvegarbage collection efficiencyVSAvoidgarbage collection time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The garbage collection process is segmented from the traditional block-level operation into page-level operations. The system divides the garbage collection task into identifying invalid pages, selecting target pages for erasure, and executing erasure only on those specific pages, rather than processing entire blocks. This segmentation dramatically reduces garbage collection time by focusing only on necessary operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adapts the garbage collection process based on the actual state of the memory. Instead of following a fixed block-erase schedule, the system continuously monitors page validity through its mapping structure and dynamically adjusts garbage collection operations to match the actual invalidation patterns, performing erasures only when and where needed.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If traditional address translation methods are used, then data access flexibility is maintained, but system complexity increases

Engineering Contradiction:
Improvedata access flexibilityVSAvoidaddress translation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system extracts the address translation function from the traditional memory controller and implements it through a dedicated mapping structure that tracks logical-to-physical address mappings. This separate mapping layer handles translation independently, simplifying the overall system architecture by clearly separating translation responsibilities from memory management operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mapping structure serves multiple functions simultaneously: it performs address translation, tracks data validity for garbage collection, and manages page allocation. This multi-functionality reduces system complexity by consolidating what would otherwise require separate mechanisms into a single unified structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4170506A1Systems, methods, and devices for ordered access of data in block modified memory
Publication Date: 2023.04.26 SAMSUNG ELECTRONICS CO LTD
  • EP4170506A1 patent drawingFigure 1~2
  • EP4170506A1 patent drawingFigure 3
  • EP4170506A1 patent drawingFigure 4

AI summary

A method may include receiving, at a memory system having a block modification characteristic, a write request for a data structure arranged in the memory, storing, based on the write request, data in the data structure, receiving, at the memory system, a read request for the data structure, reading, based on the read request, the data from the data structure, and indicating, based on the reading, the data for modification. The method may further include receiving, at the memory system, a second write request for the data structure, wherein the first write request and the second write request have an order, storing, based on the second write request, second data in the data structure, and determining, based on the read request, based on the order, the first data, wherein the reading may be further based on the determining.