Flash Memory Logical Address Space File Segmentation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The incompatibility between logical address space and file-based systems prevents effective data communication between host systems and memory systems, leading to inefficient data management and increased programming time due to frequent data consolidation and garbage collection in flash memory systems.

Innovation Solution

Divide the logical address space into distinct contiguous groups, treating each group as a separate file with unique identification, allowing direct data file storage and enabling communication between systems with different address interfaces, thereby optimizing memory usage and reducing data consolidation frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If data is stored in flash memory using traditional logical address space mapping, then the system can communicate with host systems using standard interfaces, but frequent data consolidation and garbage collection are required, increasing programming time and reducing efficiency

Engineering Contradiction:

Improveinterface compatibilityVSAvoidprogramming time

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent introduces a file system layer as an intermediary between the host system's logical address space and the flash memory's physical structure. This file system translates logical addresses into file-based addressing, enabling communication between incompatible systems while optimizing flash memory operations to reduce frequent consolidations and garbage collection, thereby decreasing programming time.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the continuous logical address space into distinct files, where each file corresponds to a specific range of logical addresses. This segmentation allows the system to manage data in discrete units that can be efficiently stored and retrieved from flash memory without requiring frequent full-block consolidations, thus improving productivity.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If flash memory erase units are increased to store multiple sectors, then storage capacity per erase unit increases, but data consolidation frequency increases, leading to increased programming time

Engineering Contradiction:

Improvestorage capacityVSAvoidprogramming time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent segments large erase units into smaller manageable files based on logical address ranges. This allows the system to work with smaller data units that can be programmed independently, reducing the time penalty associated with consolidating data across large erase units while maintaining high storage capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic file system that adapts to flash memory wear characteristics by strategically placing and managing files across different physical blocks. This dynamic management reduces the frequency and impact of garbage collection operations, thereby reducing programming time while maintaining efficient use of storage capacity.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If logical address space is divided into files with unique identification, then direct data file storage is enabled and communication between different interface systems is improved, but system complexity increases

Engineering Contradiction:

Improveinterface compatibilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal file system layer that can interface with both logical address space systems and direct file-based systems through a common framework. This multi-functional approach enables compatibility with different interface types without requiring separate complex systems for each interface type, thus managing complexity while maintaining versatility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Productivity

If data consolidation is performed frequently to maintain memory efficiency, then storage capacity utilization improves, but programming time increases

Engineering Contradiction:

Improvestorage efficiencyVSAvoidprogramming time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary organization of data into files during the initial write operation, based on logical address ranges. This preliminary action eliminates the need for frequent subsequent consolidations, as data is already optimally organized for flash memory storage, thereby maintaining high storage efficiency while minimizing programming time.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7480766B2Interfacing systems operating through a logical address space and on a direct data file basis

Publication Date: 2009.01.20 SANDISK TECHNOLOGIES LLC

AI summary

A re-programmable non-volatile semiconductor memory, such as flash memory, operates to store files with logical addresses including a unique file identifier and offsets of data within the file, termed direct data file storage. Data files generated by a host may be stored directly in such a memory through a file interface. But if a traditional host/memory interface using a continuous logical address space is being used to identify multiple files, the address space is divided into contiguous logical files, and then these files are treated in the same manner as files obtained directly from a host. Both types of interfaces may be included in the same memory system.