Understanding the Boot Process
The boot process is what happens between the moment you power on a machine (physical or virtual) and when the operating system has been completely loaded.
Like in many good video games, there are three stages for it: the initial startup performed by the hardware (again physical or virtual), the loading of the initial stages of the operating system, and then the mechanism that helps run the required services in the system. We will review the three stages in this chapter, and we will also add tips and tricks in order to intervene in a system and perform rescue operations.
In this chapter, we will cover the following topics:
- Understanding the boot process – BIOS and Unified Extensible Firmware Interface (UEFI) booting
- Working with GRUB, the bootloader, and the initrd system images
- Managing the boot sequence with systemd
- Intervening in the boot process to gain access to a system
It is very likely that you will not need...
