I have described the process of creating a system manually, as described in Chapter 5, Building a Root Filesystem, as the Roll Your Own (RYO) process. It has the advantage that you are in complete control of the software, and you can tailor it to do anything you like. If you want it to do something truly odd but innovative, or if you want to reduce the memory footprint to the smallest size possible, RYO is the way to go. But, in the vast majority of situations, building manually is a waste of time and produces inferior, unmaintainable systems.
The idea of a build system is to automate all the steps I have described up to this point. A build system should be able to build, from upstream source code, some or all of the following:
- A toolchain
- A bootloader
- A kernel
- A root filesystem
Building from upstream source code is important for a number of reasons. It means that...
