Book Image

Mastering Embedded Linux Programming - Third Edition

By : Frank Vasquez, Chris Simmonds
5 (3)
Book Image

Mastering Embedded Linux Programming - Third Edition

5 (3)
By: Frank Vasquez, Chris Simmonds

Overview of this book

If you’re looking for a book that will demystify embedded Linux, then you’ve come to the right place. Mastering Embedded Linux Programming is a fully comprehensive guide that can serve both as means to learn new things or as a handy reference. The first few chapters of this book will break down the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. After that, you will learn how to create each of these elements from scratch and automate the process using Buildroot and the Yocto Project. As you progress, the book will show you how to implement an effective storage strategy for flash memory chips and install updates to a device remotely once it’s deployed. You’ll also learn about the key aspects of writing code for embedded Linux, such as how to access hardware from apps, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters demonstrate how to debug your code, whether it resides in apps or in the Linux kernel itself. You’ll also cover the different tracers and profilers that are available for Linux so that you can quickly pinpoint any performance bottlenecks in your system. By the end of this Linux book, you’ll be able to create efficient and secure embedded devices using Linux.
Table of Contents (27 chapters)
1
Section 1: Elements of Embedded Linux
10
Section 2: System Architecture and Design Decisions
18
Section 3: Writing Embedded Applications
22
Section 4: Debugging and Optimizing Performance

Transferring the root filesystem to the target

After having created a skeleton root filesystem in your staging directory, the next task is to transfer it to the target. In the sections that follow, I will describe three possibilities:

  • initramfs: Also known as a ramdisk, this is a filesystem image that is loaded into RAM by the bootloader. Ramdisks are easy to create and have no dependencies on mass storage drivers. They can be used in fallback maintenance mode when the main root filesystem needs updating. They can even be used as the main root filesystem in small embedded devices, and they are commonly used as the early user space in mainstream Linux distributions. Remember that the contents of the root filesystem are volatile, and any changes you make in the root filesystem at runtime will be lost when the system next boots. You would need another storage type to store permanent data such as configuration parameters.
  • Disk image: This is a copy of the root filesystem formatted...