FilesystemHierarchyStandard > boot
It contains all the files essential 1 for booting your debian installation.
On some occasion (less and less often), that directory is stored on a separate partition because : 1) old bios couldn't read sector beyond a certain cylinder. 2) The boot loader doesn't understand the partition / Raid / Lvm system used for "/" partition.
For every kernel <kernel version>2 you have installed, these four files exists :
- vmlinuz-<kernel version>
- is your actual kernel binary.
- initrd.img-<kernel version>
is a small, temporary, root filesystem used solely for boot strapping your system. It takes control from your boot loader (lilo, grub, etc.), loads some essential drivers and does some essential tasks required for booting. (see mkinitramfs)
- config-<kernel version>
- contains configuration options your kernel binary was compiled with (for reference).
- system.map-<kernel version>
- contains symbol names and addresses of the linux kernel binary. It's only real use is for debugging and is non-essential the rest of the time.
Depending on your BootLoader, you may have some subdirectories too, containing binaries and/or configuration files. (like grub, chos, emile...)