On 18/12/12 01:24, Alexander Spitzer 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
Hi
This is my grub.cfg which is on usb drive that works
# Begin /boot/grub/grub.cfg
set default=0
set timeout=5
insmod ext2
set root=(hd0,1)
menuentry "Planet-Spike7" {
linux /boot/vmlinuz-3.2-lfs-7.0 root=/dev/sdc1 rootdelay=5 ro
}
the rootdelay seems to be the cure tou might want to try 10 instaed of 5
then adjust it.
It takes time for the usb to recognised
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