Linux
UEFI (ArchWiki)
> 1. - POST (Power On Self Test)
> 2. UEFI
> 3. UEFI ()
> 4. UEFI
> 5. UEFI (UEFI rEFInd ) initramfs (GRUB )
MBR55 aa0x7c00
1512440
51251232KiB (0xFFFF) (0xFFFF - 1024byte) 0x7c00MBR
EFIEFIEFI/EFI/BOOT/BOOTX64.EFI
GRUB

Linux
>GRUBOS vmlinuz-* RAM initramfs-*.img
>  vmlinuz >
>RAM (initrd) RAM
>initrdinitrdinitramfs2使
GRUBvmlinuxinitramfsinitsystemd 
VPSArch Linux/bootinitramfs-linux.img vmlinuz-linux
initramfsmkinitcpiocpio
cpio0x070707
> $ od -Ax -tx2z /boot/initramfs-linux.img
> 000000 b528 fd2f 5804 ca8c ee05 885a 1e05 1052
> ...
file  Zstandard compressed data
0x28b52ffd
Google Wikipedia Zstandard dictionary
vmlinuxMZ
file Linux kernel x86 boot executable bzImage
initramfs
zstd -d initramfs-linux.img -o initramfs-linux file initramfs-linux cpio
cpio  cpio -idv < initramfs-linux usretc
sysdev
grub
cha-boot URL