[clug] Booting without a bootloader & alternatives to /init
tony at bakeyournoodle.com
Thu May 21 00:11:13 GMT 2009
On Wed, May 20, 2009 at 09:42:01PM +1000, Ben Coughlan wrote:
> Is it possible to boot the kernel without using a bootloader? I've seen
> HOWTOs discussing how to do this with floppy disk, but I'm wondering how
> it can be done from a hard drive, or a compact flash card.
Not any more (well certainly not on an intel based system), but "syslinux"
is a really minimal bootloader for intel systems.
> Secondly; can I have the kernel run something other than /init when it's
> done booting? Ideally I would just like to call my application binary.
> Are there any services I'll be missing if I don't use /init? I don't
> need to spawn a shell anywhere, but I would like some DHCP action. I
> would also enjoy being able to pass arguments to this binary if at all
Sure you can add init=/path/to/your/app to the kernel commandline and the it
will what ever you ask. As to what you'll miss that's a tougher question.
You PID 1 will be your binary, so it will need to start sshd or any consle
services you need.
> And while I'm here; I've compiled my kernel by starting with 'make
> allnoconfig' and then rebooting/recompiling until I have a system
> running with the required drivers. Can anyone think of any boxes I
> might want to tick that may not have been noticed in this process,
> keeping in mind I want it as small and uncluttered as I can make it.
Again that depnds on your needs. For exmaple, You probably do not have
/proc or /sys support and if you'er only ever going to run your one app
you may not miss them BUT if you need to debug your app in a slightly
more "rich" environment you may :)
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