byron@cc.gatech.edu (Byron A Jeff) wrote in message news:<bdeqgv$6ab@cleon.cc.gatech.edu>...
> In article <3caa2818.0306251726.4ea2c0c4@posting.google.com >,
> Joe <joe.cooley@lycos.com> wrote:
> >Hello,
> >
> >I am attemting to install a machine that only has a USB CDROM
> >attached. I compiled and burned a 2.5.72 kernel image with all the
> >necessary drivers. The CD boots fine and asks for a root filesystem
> >floppy. I created a root filesystem image on a second CD. At the
> >prompt, I replace the kernel image CD with the root filesystem CD.
> >The kernel complains that it cannot find the filesystem at sector 0 on
> >fd0. I need to somehow get it to look at sr0, the USB CDROM device.
> >Does anyone have any idea how to go about this?
>
> It doesn't. That mechanism is solely for a floppy root.
>
> > I tried using rdev to
> >change the root device, but that didn't seem to work (could be
> >operator error).
>
> Nope. It doesn't work.
>
> > I also tried burning the kernel image and rootfs on
> >the same CD, using rdev to provide a rootfs offset to the kernel, but
> >that did not seem to work either. I tried using lilo to setup a
> >bootdisk by first creating an environment using /dev/ram, copying it
> >to a file, and mounting it over /dev/loop, but lilo didn't cooperate.
>
> The tool that you need is the Initial ramdisk, which is designed precisely
> for this purpose. The initial ramdisk is a filesystem (which can be compressed)
> that is loaded along with the kernel by the bootloader. The kernel will mount
> the initrd after booting, and will execute a program/script named linuxrc if
> it exists in the root directory of the initrd.
>
> If you want to see all of this in action, simply boot any existing distribution
> CDROM. Slackware, RedHat, gentoo, and especially KNOPPIX all use this technique
> to get going.
>
> >
> >Any documentation pointers and/or ideas would be extremely appreciated
> >- I am knee deep in coasters. I have looked into the bootdisk howto
> >among others and did not find a suitable solution.
>
> Well my confusion is why you are trying to craft this by hand? If the kernel
> recognizes and maps the USB CDROM as /dev/sr0, then any distribution worth
> its salt will pick it up upon boot.
>
> The final element that you failed to inform us: what exactly are you trying
> to install. That info would be a big help.
>
> BAJ

I need to craft this by hand (using 2.5) because the installation
machine contains a large RAID array with 2 TB of disk space and I
cannot get a normal distribution such as Debian and/or RedHat to
install. The 2.4 limit is 2 TB and some of the distros are limited to
1 TB (ascertained through experimentation).