[clug] Kernel without initramfs

David Cottrill cottrill.david at gmail.com
Wed Mar 25 07:23:10 GMT 2009

Thanks all, the big delay was coming from the debian-live initramfs
bootscripts (I'm using Debian as host too).
I believe scsi was the right place to look but it is still failing at the
same point. Have tried all variations of root=/dev/hda1, /dev/sda1 LABEL=...

Inserting a generic kernel into the same image is a serious performance hit
- these SoC motherboards are not like a standard computer, so P2 200MHz
/128MB ram is actually more like 486dx 200MHz / 100MB ram. I've built PII
400 desktops (Gentoo and Debian) and they are vastly different beast.

Even so, the boot time has been cut down enough using debootstrap instead of
cdebootstrap that I can deal with the idea of having a generic kernel (but I
will change modules=most to modules=dep). debootstrap more
accurately assesses my idea of a 'minimal' system.

When I say generic kernel - I mean Debian, not vanilla.

The setting for CONFIG_RAMFS I believe is 'y' (but support for
initrd/initramfs is 'n') so I'll give that one last crack

Now that I'm settled on not using debian-live, I have to figure out a way to
reduce the number of writes to disk. CF cards don't react well to that over
the short term and it's positively destructive medium to long term.

Interestingly I've noticed that many flash disk drive manufacturers are
pitching at the server market. Flash drives can take maybe a million hits
(cheap ones 100,000) per bit before they hit MTBF. Even with load levelling,
I'm betting most people out there could rack that up on a serious server in
a day or so.

Thanks again,

On Wed, Mar 25, 2009 at 11:52 AM, Robert Edwards <bob at cs.anu.edu.au> wrote:

> David Cottrill wrote:
>> I'm working at getting a P2 300MHz to boot in a reasonable time - the
>> initramfs runtime on a generic kernel is about 2 minutes.To fix this I've
>> built and will be rebuilding a custom kernel with all the required modules
>> built in.
>> What I've done - lsmod from the generic kernel, made sure all modules
>> listed
>> got included in the kernel in my custom version.
>> The remaining problem: After finding all my devices (including my hard
>> disk)
>> the boot sequence fails to mount the root partition (local).
>> The first and last error message is:
>> VFS: can't mount (insert disk label or /dev/hda1 or /dev/sda1 or anything
>> else here) or block (0,0)
>> Please append a correct root=... Choose from the following partitions:
>> There isn't a list of partitions to choose from so I guess it is the
>> problem
>> is in the part of the kernel that recognises partitions but my most recent
>> build included almost all of the partition options so I'm a little bit
>> mystified.
>> Any suggestions?
>> Thanks,
>> David
> Are you compiling a kernel.org kernel or one from the Ubuntu kernel
> source packages? The Ubuntu kernel sources include patches to find
> the root file system by disk label. You probably should identify your
> root fs by block device instead (eg. root=/dev/sda1 etc.) (and in
> fstab as well...).
> Cheers,
> Bob Edwards.

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