Regarding Kernel

Ken Moffat ken at kenmoffat.uklinux.net
Tue May 31 05:02:42 PDT 2005


On Tue, 31 May 2005, Chakkaradeep C C wrote:

> hi,
>
> fine....so what about Initial RAM disk?..if i want it in my
> system........i should have  "modprobe.conf",so what to do then?? :-(
>
> with regards,
> C.C.Chakkaradeep
>
> On 5/31/05, Ken Moffat <ken at kenmoffat.uklinux.net> wrote:
[snip my earlier]
> >
> >  Why do you think you _need_ a modprobe.conf ?


 Ok, it sounds as if you've been reading the mass of often wrong, or
at best partial, documentation out there on building initrds :)  Any
documentation on initrds is focussed on a specific task (rescue disk,
installer, embedded system), so some of what you read will be specific
to particular host systems or particular targets.

 My only relevant experience with an initrd was using a uClibc rootfs
(yes, the binary download) to build a rescue CD for my own x86 machines
(2.6.10-as kernel).  It works adequately, but it isn't pretty.  I didn't
need modprobe.conf.

 My method: strip the kernel down, use modules for things that aren't
needed to bring the box up - net drivers, msdos fs, usb, scsi [ none of
my boxes have scsi CD ], boot, find the CD, mount it at /usr, do not use
any existing disk.  Read the "creating a custom boot disk" section in
version 5.1 of the blfs book.  I used a static /dev directory, with an
absolute minimum of devices, the problem with eltorito boot images is
fitting everything into 2.88MB.  For a rescue CD, you can load modules
from the CD after you've booted.  For a "distro" installer you may have
to do a lot more (e.g. to access scsi disks or usb keyboards).

 Going back to your modprobe.conf, I think it will allow modules to be
configured (e.g. passing non-standard port/interrupt numbers to the old
sb16 sound card).  Maybe it's necessary to automatically load cloop (e.g
knoppix-style installers), similar to the way it is needed to associate
eth0 with the actual network driver.  For an installer, you may be able
to generate one at runtime, based on what hardware you detect and what
responses you get from the user.

 Any follow-ups to lfs-chat please.

Ken
-- 
 das eine Mal als Tragödie, das andere Mal als Farce




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