miniroot [Was: Re: New hpcboot200 - please test]

["Christer O. Andersson" <christer%a-son.net@localhost>]

On Thu, Mar 09, 2006 at 12:02:47AM -0500, Michael Wileman wrote:
> On Thu, 9 Mar 2006, Valeriy E. Ushakov wrote:
> 
> >On Wed, Mar 08, 2006 at 21:27:02 -0500, Michael Wileman wrote:
> >
> >>Is there a web page somewhere that explains all the boot options
> >>possible? I have booted from wd and by nfs (with fixed ip compiled
> >>into kernel), but haven't heard of detached rootfs or install kernel
> >>before.
> >
> >You can have a root fs image (md0) embedded into the kernel, or you
> >can have a detached root fs image that hpcboot will load into memory
> >along with the kernel.
> >
> >Install kernel has an fs image embedded and it is compiled to always
> >use that as root fs, regardless of the boot options.
> >
> What are the uses for these various options. I assume that install 
> kernel is for installation, but why have embedded root fs or detached 
> root fs as opposed to a standard root fs?
> 
> Mike

Install kernel is used for installing NetBSD on your system. The
install kernel carries it's own miniroot fs. The reason to use a
miniroot is that you have your fs right away, you don't have to
bring up network interfaces or mount disks. Then you can start
searching for available possibilities to mount and create a proper
file system.

A detached miniroot is a complete fs, that is a separate file that
the bootloader loads together with the kernel. The kernel (at least
at present) still needs to be compiled with options for using the
miniroot, but you don't have to embed it into the kernel (with
mdsetimage). This saves a couple of steps when creating a new kernel
and also reduces the amount of data to be transferred to your cf
each time you try out a new kernel miniroot combination.

-- 
Christer O. Andersson
Odensbacken