BusyBox and Linux initialization
This chapter introduces BusyBox. We also look at adding a display to the thermostat, and follow the system initialization process from power on to login prompt. Following a brief review of the history of BusyBox, we look at the process of configuring and building it. The process is very similar to the Linux kernel. There is a detailed discussion of the distinction between hard links and symbolic, or soft, links.
We use a combination of framebuffer driver and console driver to create a simple text-only display for the thermostat using ANSI terminal escape sequences. Then we trace the four-stage boot process, and show how to get the thermostat application started at boot time.