To fully understand all Android internals, we are going to learn how the whole boot sequence works: from the power-on to the actual Android system boot. The Android boot sequence is similar to any other embedded system based on Linux: in a very abstract way, after the power-on, the system initializes the hardware, loads the kernel, and finally the Android framework. Any Linux-based system undergoes a similar process during its boot sequence: your Ubuntu computer or even your home DSL router.
In the next sections, we are going to dive deeper in to these steps to fully comprehend the operating system we love so much.
When you press the power button on your device, the system loads a tiny amount of code, stored inside a ROM memory. You can think about this as an equivalent of the BIOS software you have in your PC. This software is in charge of setting up all the parameters for CPU clock and running the RAM memory check. After this, the system loads the...