1. /boot directory:
* vmlinuz: This file contains the Linux kernel itself, which is loaded into memory during boot.
* initrd.img (or initramfs.img): This file contains the initial ramdisk, which is a small, self-contained filesystem that is loaded before the main root filesystem is mounted. It contains drivers and utilities needed for early boot stages.
* grub.cfg (or grub2.cfg): This file contains the configuration for the GRUB bootloader. It defines the boot menu, kernel parameters, and other boot-related options.
* config- files: These files contain the configuration information for various kernel modules.
* System.map: This file maps kernel symbols to their memory addresses.
2. /etc directory:
* fstab: This file defines the file systems that are mounted at boot time, including the root filesystem.
* rc.local (or rc.sysinit): This file contains scripts that are run at boot time.
* mtab: This file stores the current mount points for all mounted filesystems.
3. /sys directory:
* firmware/efi/efivars/ directory: This directory contains EFI variables which store boot-related configuration information.
* devices/virtual/disk/by-id directory: This directory contains symlinks to device files for hard drives and partitions, which are used for boot.
4. BIOS/UEFI firmware:
* The BIOS or UEFI firmware also contains boot-related settings, such as boot order and hard drive settings.
5. Other files:
* /proc/cmdline: This file contains the kernel command line parameters passed to the kernel at boot time.
* /var/log/boot.log: This file logs boot messages.
Important points to note:
* The boot process is complex and involves interaction between multiple components.
* The specific files and directories involved can vary depending on the Linux distribution and boot loader used.
* Modifying boot files requires careful attention and should only be done by experienced users.
It's best to consult your distribution's documentation for specific information regarding boot files and their configuration.