I got it to work! Turns out that the root file system changes to /dev/sdc1
after all the harddisks are found so changing the line root=/dev/sda1 to
root=/dev/sdc1 and adding a rootdelay successfully booted the system!
Now it would be nice for it to work using UUIDs so the booting can
be independent of host system.
Also, the scrollback buffer does work just not when the kernel has crashed.
I am sorry for the long kind of useless post but if anyone has anything to
add please feel free.
On Mon, Dec 17, 2012 at 5:24 PM, Alexander Spitzer <aes...@cornell.edu>wrote:
> Hello all,
>
> I am having a hard time booting my LFS system, which is on a USB drive. I
> installed grub on /dev/sdc (the usb relative to the host) and the bios
> successfully finds GRUB. After around 2.3 seconds, the boot process hangs
> after printing what I believe to be a trace call. Interestingly, one time
> when I booted the trace call was short enough for me to write down the
> error which I can't normally see due to the length of the trace prints.
> Here is the error:
>
> Kernel panic-not syncing: VFS: Unable to mount root fs on unknown
> block(0,0)
>
> What exactly does "unknown block(0,0)" mean?
>
> The problem appears to be that the kernel can't find the root file system.
> How can that be a problem, if the kernel, which is ON the root file system,
> was found and ran?
> Here is the grub.cfg file:
> # Begin /boot/grub/grub.cfg
> set default=0
> set timeout=5
>
> insmod ext2
> set root=(hd0,1)
>
> menuentry "GNU/Linux, Linux 3.7-lfs-SVN-20121212" {
> linux /boot/vmlinuz-3.7-lfs-SVN-20121212 root=/dev/sda1 ro
> }
>
> I believe the USB is always sda because to boot I do a manual boot
> override and select USB from the BIOS menu. The grub command line also
> confirms this.
>
> Searching online, there were some suggestions that the kernel was compiled
> without support for necessary file systems and hardware. I check my config
> file for the kernel and found all the important options to be set to yes
> (USB_mass_storage, ext3 filesystem, USB UHCI, USB OHCI, and several scsi
> ones). There are however many USB options that are not set. Are there any
> specific ones that should be set for the kernel to load the root filesystem?
>
> Also, I've tried unsuccessfully to read more of the boot output by two
> methods: increasing the resolution and scrolling back. The scroll back
> buffer is set to yes in the kernel config yet shift page down and shift
> page up do nothing. Also, vga=791 is deprecated and I haven't been able to
> get any effect by using "set vgxpayload=1024x728".
> How can I read the boot print outputs without a high speed camera?
>
> Thanks,
> Alex
>
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