Flash File System Block Allocation for Data Relocation

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Solution Overview

Problem

Existing file systems for flash memory require entire blocks to be erased for rewriting data, leading to inefficient memory usage and system performance issues, especially in hand-held devices where uninterrupted access and low access delays are desired.

Innovation Solution

A file system that allocates a block exclusively for linear files and allows non-linear files to be stored in shared blocks, enabling efficient sharing and reducing the need for data relocation during rewriting operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If entire blocks are erased for rewriting data in flash memory, then data can be stored and modified, but memory usage becomes inefficient and system performance deteriorates due to data relocation requirements

Engineering Contradiction:

Improvedata storage reliabilityVSAvoidsystem throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments files into two categories: linear files that require exclusive block allocation and non-linear files that can share blocks. This segmentation allows the system to handle different file types with appropriate storage strategies, improving overall system efficiency while maintaining data reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic block allocation where blocks can be exclusively assigned to linear files when needed and shared among non-linear files when appropriate. This dynamic approach allows the file system to adapt to different access patterns and file requirements, optimizing both reliability and performance.

Inventive Principle:

Principle #15Dynamics

2Ease of manufacture

If data of other files is relocated when a sector needs to be erased, then rewriting can proceed, but system throughput decreases due to additional relocation operations

Engineering Contradiction:

Improverewriting capabilityVSAvoidaccess delay

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by allocating exclusive blocks to linear files in advance, preventing the need for data relocation during rewriting operations. This preliminary allocation ensures that when erasure is needed, no other files are affected and relocation operations are avoided, reducing access delays.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If files are stored in non-contiguous blocks to share sectors, then memory usage improves, but system performance deteriorates due to segmented file structure requiring new access sequences

Engineering Contradiction:

Improvememory utilizationVSAvoiddata access speed

Core Design Contradiction:

Quantity of substanceVSSpeed

Solution Approach 1:

The patent segments files into linear and non-linear categories, allowing linear files to maintain contiguous storage for fast access while non-linear files can be fragmented to maximize memory utilization. This segmentation resolves the contradiction by applying different storage strategies to different file types.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different storage quality characteristics to different files: linear files receive contiguous, exclusive block allocation for high-speed access, while non-linear files are allowed fragmented, shared block allocation for optimized memory usage. This local quality differentiation allows the system to achieve both goals simultaneously.

Inventive Principle:

Principle #3Local quality

4Reliability

If files are copied from flash memory to RAM at system start-up, then uninterrupted read access is achieved, but memory usage increases due to duplication of files

Engineering Contradiction:

Improveread access continuityVSAvoidmemory consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9003354B2Optimizing memory usage and system performance in a file system requiring entire blocks to be erased for rewriting data

Publication Date: 2015.04.07 TEXAS INSTRUMENTS INC

AI summary

A file system which ensures that some of the (desired) files (“linear files”) are stored in corresponding exclusive blocks (i.e., a block that stores data corresponding to one file only). Due to such a feature, rewriting of data corresponding to other files would not cause data corresponding to linear files to be relocated/rewritten. Such a feature may provide reliable and steady retrieval of data of the corresponding file from a flash memory organized as sectors. According to another aspect, some of the files (“non-linear files”) are stored in non-exclusive blocks (i.e., multiple files can share the same block or the same file can span multiple blocks without contiguity).