Chapter 5. Building a Root Filesystem
The root filesystem is the fourth and final element of embedded Linux. Once you have read this chapter, you will be able build, boot, and run a simple embedded Linux system.
This chapter explores the fundamental concepts behind the root filesystem by building one from scratch. The main aim is to provide the background information that you need to understand and make best use of build systems like Buildroot and the Yocto Project, which I will cover in Chapter 6, Selecting a Build System.
The techniques I will describe here are broadly known as roll your own or RYO. Back in the earlier days of embedded Linux, it was the only way to create a root filesystem. There are still some use cases where an RYO root filesystem is applicable, for example, when the amount of RAM or storage is very limited, for quick demonstrations, or for any case in which your requirements are not (easily) covered by the standard build system tools. Nevertheless, these cases are quite...