Describe the Linux boot process.

1. Firmware (BIOS/UEFI) runs POST and finds a boot loader. 2. Boot loader (GRUB2) loads the kernel and initramfs. 3. Kernel initialises hardware, mounts initramfs, which loads drivers needed to mount the real root filesystem. 4. systemd (PID 1) starts and brings the system to the default target (multi-user.target or graphical.target).