initramfs - как это работает

he boot process for recent versions of Debian/Ubuntu works
something like this: GRUB loads the kernel and initramfs image; the
kernel ungzips and un-cpio's the initramfs it's been given into a ramfs
filesystem mounted as /, and runs /init on it. /init is responsible for
loading drivers (nowadays by starting udev), setting up software RAID or
LVM where applicable, and mounting the root filesystem as /root. Virtual
filesystems like /dev, /sys and /proc are moved into /root. Then /init
runs run-init from the klibc package, which deletes all the files on the
initramfs (to save memory), chdir()s into /root and does a
mount --move /root /. Then it runs /sbin/init from the real root
filesystem and the machine boots normally.