Embedded Linux

6.

The Root Filesystem

6.1.

Filesystem Architecture

6.1.1.

Filesystem Hierarchy Standard (FHS)

6.1.1.1.

Standard Directory Layout

6.1.1.2.

Directory Purposes

6.1.1.3.

Compliance Considerations

6.1.2.

Essential Directories

6.1.2.1.

6.1.2.2.

/lib and /lib64

6.1.2.3.

6.1.2.4.

/etc Configuration

6.1.2.5.

/dev Device Files

6.1.2.6.

/proc and /sys Virtual Filesystems

6.1.2.7.

/tmp and /var Variable Data

6.1.2.8.

/home User Directories

6.2.

C Library Selection

6.2.1.

Library Comparison

6.2.1.1.

Feature Comparison

6.2.1.2.

Size Comparison

6.2.1.3.

Performance Comparison

6.2.2.

6.2.2.1.

Features and Compatibility

6.2.2.2.

POSIX Compliance

6.2.2.3.

Size Considerations

6.2.3.

6.2.3.1.

Embedded System Focus

6.2.3.2.

Configuration Options

6.2.3.3.

Compatibility Issues

6.2.4.

6.2.4.1.

Lightweight Design

6.2.4.2.

Standards Compliance

6.2.4.3.

Static Linking Support

6.3.

Core System Utilities

6.3.1.

BusyBox Integration

6.3.1.1.

The Swiss Army Knife Concept

6.3.1.2.

Applet Architecture

6.3.1.3.

Size and Functionality Trade-offs

6.3.2.

BusyBox Configuration

6.3.2.1.

Configuration System

6.3.2.2.

Applet Selection

6.3.2.3.

Feature Customization

6.3.3.

BusyBox Installation

6.3.3.1.

Compilation Process

6.3.3.2.

Installation Methods

6.3.3.3.

Symlink Creation

6.3.4.

Alternative Utility Suites

6.3.4.1.

6.3.4.2.

6.3.4.3.

Embedded-Specific Tools

6.4.

System Initialization

6.4.1.

Init System Overview

6.4.1.1.

Role of Init Process

6.4.1.2.

Init System Types

6.4.1.3.

Service Management

6.4.2.

6.4.2.1.

Traditional Init System

6.4.2.2.

6.4.2.3.

6.4.2.4.

Service Dependencies

6.4.3.

6.4.3.1.

Modern Init System

6.4.3.2.

6.4.3.3.

Service Management

6.4.3.4.

Dependency Handling

6.4.4.

6.4.4.1.

Dependency-Based Init

6.4.4.2.

Service Scripts

6.4.4.3.

Configuration Files

6.4.5.

Custom Init Systems

6.4.5.1.

Simple Init Scripts

6.4.5.2.

Embedded-Specific Solutions

6.5.

Device Management

6.5.1.

Static Device Files

6.5.1.1.

Device File Creation

6.5.1.2.

Major and Minor Numbers

6.5.1.3.

6.5.2.

Dynamic Device Management

6.5.2.1.

6.5.2.2.

6.5.2.3.

6.5.3.

Device Permissions

6.5.3.1.

User and Group Access

6.5.3.2.

Device Security

6.6.

Filesystem Creation

6.6.1.

Manual Filesystem Creation

6.6.1.1.

Directory Structure Setup

6.6.1.2.

File Population

6.6.1.3.

Permission Setting

6.6.2.

Automated Filesystem Creation

6.6.2.1.

Build System Integration

6.6.2.2.

Filesystem Generation Scripts

6.6.3.

Filesystem Validation

6.6.3.1.

Structure Verification

6.6.3.2.

Dependency Checking

6.6.4.

Filesystem Types for Embedded

6.6.4.1.

ext4 Filesystem

6.6.4.2.

JFFS2 for NOR Flash

6.6.4.3.

UBIFS for NAND Flash

6.6.4.4.

SquashFS Read-Only

6.6.4.5.

CRAMFS Compressed

6.6.4.6.

YAFFS2 Flash Filesystem

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