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Introduction
The text is divided into ten chapters and two appendices.
Chapter 1, “Introduction,” gives a brief history of embedded Linux and
what the benefits of embedded Linux are over other RTOSs. It discusses in
detail the features of various open source and commercial embedded Linux
distributions available. The chapter concludes by presenting a transition roadmap
from a traditional RTOS to embedded Linux.
Chapter 2, “Getting Started,” explains the architecture of embedded Linux
and compares it with traditional RTOS and microkernel architectures. In brief
various Linux kernel subsystems such as the hardware abstraction layer,
memory management, scheduler, file system, and so on are given. A small
description of the user-space Linux programming model is also given. The
second half of the chapter explains the Linux start-up sequence, from bootloaders
to kernel start-up and user-space start-up scripts. The last section
explains the steps involved in building a GNU cross-platform toolchain.
Chapter 3, “Board Support Package,” explains bootloader architecture followed
by a discussion on the system memory map, both hardware and
software memory maps. The second half of the chapter explains interrupt
management, the PCI subsystem, timers, UART, and power management in
detail.
Chapter 4, “Embedded Storage,” explains the MTD subsystem architecture
for accessing flash devices. The second half of the chapter discusses various
embedded file systems such as RAMFS, CRAMFS, JFFS2, NFS, and so on. The
chapter also discusses various methods for optimizing storage space in an
embedded system, both kernel and user-space optimizations. A discussion of
various applications designed for embedded Linux such as Busybox is given.
Finally some steps for tuning the kernel memory are given.
Chapter 5, “Embedded Drivers,” discusses in detail various embedded
drivers such as the Serial driver, Ethernet driver, I2C subsystem, and USB
gadgets.
