Re: [gentoo-user] eject and util-linux blocker

[Rich Freeman <rich0@gentoo.org>]

On Wed, Mar 18, 2015 at 2:12 PM, Dale <rdalek1967@gmail.com> wrote:
>
> I thought there was a tool that just lists the contents.  Things is, I'm
> not sure what I would be looking at.

An initramfs is just a root filesystem.  init is /sbin/init unless the
kernel is told otherwise.

If you took your entire root filesystem, compressed it into a cpio
archive, and put that in grub as your initramfs, then your entire
distro would run from a ramdisk and you might not even notice the
difference (well, assuming you had enough RAM).

The only real "magic" with an initramfs is that it mounts your real
root somewhere, then swaps it out for the real root:
http://manpages.courier-mta.org/htmlman8/switch_root.8.html

This is a bit like chroot, but the old root filesystem is deleted in
the process (so that your initramfs does not consume any RAM once the
system actually boots).  I'm not sure exactly how dracut does it with
systemd, since my understanding is that during shutdown systemd
actually pivots back to the initramfs (which allows all filesystems to
be cleanly unmounted instead of merely being mounted read-only).

-- 
Rich