[gentoo-amd64] Re: Can initrd and/or RAID be disabled at boot?

[Duncan]

Duncan posted on Thu, 27 Jun 2013 18:53:08 +0000 as excerpted:

> But unfortunately, I've not actually tried the noinitrd kernel
> commandline option, so I can't VERIFY that it works here, with my now
> builtin initramfs.  I'll have to reboot to try that, and will try to get
> back to you on that.  (Note to self.  Test the root=LABEL with
> initramfs-less boot too, while I'm at it.)

I couldn't get the noinitrd option to work here either, on builtin 
initramfs.

Not too big a deal tho because as I think you (Mark, grandparent poster) 
suggested, it's always possible to rebuild a new kernel without the 
initramfs built-in.  And if a kernel fails with its builtin for some 
reason, there's still the previous kernels with their known working 
builtins.  So just as I can always boot a backup kernel when a new kernel 
fails, I can always boot a backup kernel when the builtin initramfs fails.

Which of course means I didn't try the root=LABEL without an initramfs.

But one other option I DID try... rdinit= .  This parameter is similar to 
the init= parameter, but for the initr*.  It is thus possible to, for 
instance, do something like rdinit=/bin/bash (assuming that's the shell 
available in your initr*), and get a direct initrd shell, instead of the 
script that /bin/init usually is in the initr*.  Then in that shell you 
can do whatever manual thing you want, and possibly finish up with an 
exec /bin/init or whatever, to run the normal rdinit script.

Of course another option would be to setup multiple scripts in the initr*, 
each of which could be run as the rdinit replacement, but doing different 
things.  It would then obviously be possible to have one of those scripts 
do something else entirely, whether that be mounting a different root, or 
running a memory checker, or starting a game (either in the initr* itself 
or mounting a different root to do it), or...

You could then set rdinit= in the kernel commandline to select the 
replacement rdinit script you wanted.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman