Re: [gentoo-dev] Re: Questions about SystemD and OpenRC

[Mike Gilbert]

On Sun, Aug 12, 2012 at 8:25 AM, Rich Freeman <rich0@g.o> wrote:
> I think that people get this confused because 99% of linux users have
> an initramfs (and about 2% of Gentoo users it seems), and most
> initramfs implementations DO interpret the root=parameter.  If you
> specify an initramfs then the kernel actually ignores the
> root=parameter entirely, mounting the initramfs as root, and passing
> control to its init.  The initramfs is expected to mount root (or not
> - you could just run the whole system off an initramfs I guess).  Most
> initramfs implementations just parse the root= line on the kernel,
> although it is worth noting that genkernel's initramfs does not and
> uses real_root instead.

Small correction: genkernel's /init script accepts both real_root and
root on the kernel command line. If real_root is not specified, the
value of root is used.

It seems that the real_root option is a remnant of the initrd (not
intramfs) code, where root needed to be a ram disk (/dev/ram0). With
initramfs, the kernel ignores root, so we are free to use it for
specifying the actual root device.

So, when you see grub2-mkconfig generating entries with root=...,
please do not panic; this works just fine. :-)