Considering the current technology trend, Linux is the next big thing. Linux has consistently released cutting-edge open source products, and embedded systems have been added to the technological portfolio of mankind.
The Yocto Project is in an optimal position to be the choice for your projects; it provides a rich set of tools to help you to use most of your energy and resources in your product development, instead of reinventing the wheel.
The usual tasks and requirements for embedded Linux-based products and development teams were the guidelines for this book's conception. Written by active community members with a practical and straightforward approach, it is a stepping stone for both your learning curve and your product's project.
Chapter 1, Meeting the Yocto Project, presents the history of the Yocto Project, showing the parts that compose it.
Chapter 2, Baking Our Poky-based System, introduces the environment needed for the first build.
Chapter 3, Using Hob to Bake an Image, shows the user-friendly graphical interface that can be used as a wrapper for configuration and as a build tool.
Chapter 4, Grasping the BitBake Tool, presents the first concepts and premises of the tool used to control all other pieces of the Yocto Project.
Chapter 5, Detailing the Temporary Build Directory, details the output directory tree of a build with focus on the tmp directory.
Chapter 6, Assimilating Packaging Support, introduces the package concepts and details the packaging support used by the Yocto Project.
Chapter 7, Diving into BitBake Metadata, details the concepts and syntaxes used by the Yocto Project metadata, both in recipes and configuration files.
Chapter 8, Developing with the Yocto Project, details how to use the Yocto Project to generate a custom development environment.
Chapter 9, Debugging with the Yocto Project, details which debug tools the Yocto Project provides and how to use them.
Chapter 10, Exploring External Layers, explores one of the most important concepts of the Yocto Project, which is the flexibility of using external layers.
Chapter 11, Creating Custom Layers, practices the steps of creation of layers.
Chapter 12, Customizing Existing Recipes, lists the common use cases of recipe customization and how to achieve them properly.
Chapter 13, Achieving GPL Compliance, summarizes the tasks and concepts involved in a copyleft compliance product.
Chapter 14, Booting Our Custom Embedded Linux, uses a real hardware machine together with the Yocto Project's tools.
Appendix, References, lists the references used in the book.
To better understand this book, it is important that you have some previous background in some topics that are not covered or are just briefly mentioned along the text.
A basic understanding of the GNU/Linux environment usage and embedded Linux is important along with general concepts used in development as compilation, debugging, deployment, and installation. Some experience with Shell Script and Python is a bonus because these programming languages are core technologies used extensively by the Yocto Project's tools.
However, the concepts enumerated should not discourage you from reading this book as they can be learned concurrently.
This book is intended to be read by engineers and enthusiasts with embedded Linux experience willing to learn the Yocto Project's tools for evaluation, comparison, or use in a project. This book is aimed to get you up to speed quickly and to prevent you from getting trapped by the usual learning curve pitfalls.
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Throughout the book, we will use build as the build directory."
A block of code is set as follows:
BB_NUMBER_THREADS ?= "${@oe.utils.cpu_count()}"
PARALLEL_MAKE ?= "-j ${@oe.utils.cpu_count()}"
MACHINE ??= "qemux86"Any command-line input or output is written as follows:
$: sudo apt-get install gawk wget git-core diffstat unzip texinfo build-essential chrpath
New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "If we plan to build a standard image, we can click on Build Image and wait for BitBake to run the required tasks to build it."
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