Linux system crash

noelc · 05-06-2010, 10:02 PM

Can you help.

I have been useing Linux (Ubuntu) for a while now and recently updated to the latest version of Ubuntu.

Now I can NOT boot up my PC I,m getting the following error message during the booting process

mount:mounting none on /dev failed: No such device

Please help

catkin · 05-07-2010, 01:07 AM

That's not a crash, it's a boot failure.

You may get better replies if you make the thread title more meaningful, something like "ubuntu upgrade: mount fails on boot"

RockDoctor · 05-07-2010, 06:05 AM

Quote:

Originally Posted by noelc

Can you help.

I have been useing Linux (Ubuntu) for a while now and recently updated to the latest version of Ubuntu.

Now I can NOT boot up my PC I,m getting the following error message during the booting process

mount:mounting none on /dev failed: No such device

Please help

corrupt /etc/fstab?? just a guess

catkin · 05-07-2010, 07:18 AM

Quote:

Originally Posted by RockDoctor

corrupt /etc/fstab?? just a guess

Good guess. "none" is used for the usb file system, something like

Code:

none            /proc/bus/usb  usbfs       devgid=765,devmode=664     0 0

but the devgid value in that line will not be correct for ubuntu. Anybody know what ubuntu uses?

If fstab is corrupt the solution will be to try booting to single user mode (assuming the fstab entry for / is still OK and ubuntu's unusual version of single user mode allows it) or to boot a Linux from other media such as an installation or Knoppix CD-or-DVD, mount the ubuntu / in write mode and edit fstab to fix.

Laurens73 · 05-07-2010, 08:32 AM

I compared the fstab with my running system over here, and no line in /etc/fstab points to /proc/bus/usb anymore. This is a 9.10 (Karmic Koala) machine btw.

Other Ubuntu users seem to use the next settings with 9.04 (Jaunty Jackalope):

Code:

none /proc/bus/usb usbfs devgid=123,devmode=664 0 0

But if you want to see what the group ID of a certain group is to let users get access to a usb device, looking in /etc/group should give the correct information.

catkin · 05-07-2010, 08:54 AM

Quote:

Originally Posted by Laurens73

I compared the fstab with my running system over here, and no line in /etc/fstab points to /proc/bus/usb anymore. This is a 9.10 (Karmic Koala) machine btw.

Maybe the problem is that it is no longer required but has not been cleanly removed from the fstab.

Laurens73 · 05-07-2010, 01:06 PM

Quote:

Originally Posted by catkin

Maybe the problem is that it is no longer required but has not been cleanly removed from the fstab.

At least it's a thing noelc can try: either removing or quoting the line or replacing it for a suitable one like above. In my fast search I haven't found a bug issue at the official Ubuntu sites related to this one.

brucehinrichs · 05-07-2010, 02:28 PM

Comment it out and reboot; or comment it out,replace with the above (in case it really is needed); then reboot?
Either way, I would comment it instead of removing or replacing, you can delete it later, when you get it working.

noelc · 05-08-2010, 02:32 AM

Guys I appreciate the comments but I must admit I not that experienced with Linux to understand how to action your proposed solutions

brucehinrichs · 05-09-2010, 11:31 AM

Posting the output of

Code:

cat /etc/fstab

would help. And please wrap the output in [CODE][CODE] tags (it's easier to read). To do that click on 'Post Reply' (as opposed to 'Quick Reply). In this mode you'll have a toolbar available. The [CODE] tags are the '#' sign button.

catkin · 05-09-2010, 12:02 PM

Quote:

Originally Posted by noelc

Guys I appreciate the comments but I must admit I not that experienced with Linux to understand how to action your proposed solutions

Can you use GRUB to choose "singe user mode" (or something like that)?

Is the failed OS on this computer the only one that is capable of mounting the ubuntu / file system?

If so you will need to boot something else that can mount it so you can look at and edit /etc/fstab. That may be possible using an ubuntu installation CD-or-DVD. If not then you could boot something like a Knoppix DVD.

Please tell us which part of these ideas you do not understand and what you do understand.