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jamespetts 01-06-2012 03:03 PM

Cannot boot after BIOS settings lost
My parents, for whom I have in the past set up computers running Ubnutu 11.10, had a power cut last night, after which they cannot boot one of the networked three computers in the house. Unfortunately, that is the computer on which all their documents are stored (there is a backup, but that is all in Deja Dup's compressed format).

The BIOS's battery seems to be flat, as, after the 5 hour power cut, the BIOS settings were lost. I was able, over the telephone, to tell my father what the correct BIOS settings were such that he was able to get past the "insert correct boot device" message, but there is now a new and more puzzling problem.

The computer is a little old, and uses a P4C800-E Deluxe motherboard. The onboard IDE controller seems to have stopped functioning properly a while ago, so we had been using the add-on Promise controller, in non-RAID mode. D1 is the boot drive, an SSD, and D0 is a separate hard drive containing all the documents. The boot configuration is now set for D1 to be the boot drive.

When Linux is booted, the correct Ubuntu loading screen is shown, but the session eventually drops into a "busybox" shell without getting as far as the login screen. From either there or a recovery session, it is apparent that the filesysetm shown is not the filesystem that is actually on the boot device: /etc/fstab does not exist, for example; /root is empty, and there is no /home (which would normally be mounted as the additional HDD). There is also no /mnt or /backup which are root level directories which I had created.

After a failed start or two, the GRUB screen presented itself, and the option of a recovery mode was made available. When this was selected, there was, I am told, a printed error message in the system messages relating to being unable to mount a drive "by-uuid/[many seemingly random digits that my father did not read, which I am presuming is a UUID]".

I am afraid that I am somewhat puzzled by this, or how to correct it (which is made more difficult by the fact that I am not next to the computer to interact with it directly).

Does anyone have any ideas as to what the trouble might be, or how to go about investigating it further/fixing it? I should be very grateful indeed for any thoughts.

igadoter 01-06-2012 03:09 PM

Remove hard disk and buy another - a working computer and install the disk. At least you will save your data. If on your father computer is Windows installed it may not work at all. Even a slight change of a hardware configuration may cause Windows to stop to boot.

jamespetts 01-06-2012 04:36 PM

No, Windows is not installed on any of the computers in the house; and it was working before the power cut, so it seems rather soon to give up on it now, especially since my parents have recently bought an entirely new computer to replace another that had decidedly failed (motherboard - vintage 2002 - capacitors gone). The next step if the problem cannot be fixed directly is simply to reformat and re-install Linux on the OS drive, leaving the separate drive with the documents intact; but it would be heplful if there might be a means of finding a solution rather less drastic.

rokytnji 01-06-2012 04:42 PM

If me. I would try

jamespetts 01-06-2012 04:59 PM

Hmm, good idea - I'll tell my father to give that a try.

rokytnji 01-06-2012 05:04 PM

At the cost of a download and a cdr disk. A live Parted Magic Iso with a current Gparted will do a fsck through Gparted after booting up live. Just be sure to unmount any partitions before you are going to run a fsck on.

I remember a post also where a SlaX CD was good for this also

jamespetts 01-06-2012 05:13 PM

Ahh, thank you for the tip. Does the Ubuntu Live CD have such a tool?

rokytnji 01-06-2012 05:15 PM

Yeah, but in that Ubuntu thread I posted They complain that the Ubuntu live CD does not do the job as well as Slax or Parted Magic.

Edit: There is a bug report on that.

jamespetts 01-06-2012 05:23 PM

Interesting - thank you for that. I have told him to use the sudo shutdown -rF command for the time being - will that assist, do you think?

rokytnji 01-06-2012 05:30 PM

Don't know since I don't run Ubuntu as you can see from my profile.

For me I keep a Parted Magic live CD like a wrench in a toolbox for situations like this when a improper shutdown scrambles a file system.

I have repaired my ext2 USB Puppy Linux installs when improper shutdown corrupted my pendrive and boot would not happen. Just be sure file system is unmounted, (I can't stress that enough), because you will damage the partition even further if it is mounted when doing a fsck.

jamespetts 01-06-2012 05:34 PM

Hmm - I think that that is the purpose of the shutdown/reboot fsck procedure - to run when unmounted. I don't have a Parted Magic live CD, but I might be able to give my father instructions to create one; but that might take some time.

How would one run fsck from a Parted Magic live CD (bearing in mind that I shall have to give instructions to my father by telephone or by e-mail, and I have not used the software before)?

rokytnji 01-06-2012 05:36 PM

Just open Gparted. Right click on the Partition you want to check. If mounted pick unmount in right click menu. Then after it processes. Right click the partition again and pick Check from the menu.

Simple and easy.

jamespetts 01-06-2012 06:02 PM

Lovely, thank you for that. I shall tell my father to do that if the reboot fsck fails. Thank you for your help.

jamespetts 01-11-2012 07:02 AM

No FSCK result yet, but I gave my father a Gparted disc recently, and he reports that it tells him the following on bootup:


I had tried to used the disc & got to a screen which gives a list of available drives & their partitions.
These were listed as:-
./dev/mapper/pdc_cbchhfhfj (111.80 GiB)
/dev/sda (596.17 GiB)
/dev/sdb (55.90 GiB)

The second (/dev/sda) is shown as unallocated, whilst the third (/dev/sdb) is shown as having the following partitions
/dev/sdb2 extended
/dev/sdb5 ext4 33.85
unallocated 1.0 MB
/dev/sdb1 linux-swap 1.91 Gib boot
Does this by itself give any indication of the problem? This looks slightly odd to me, but I am not used to the Gparted boot disc, so I am not sure whether I should expect to see something like this here or not.

How does one instigate a filesystem check when booting from a Gparted disc?

Thank you for your help with this!

rokytnji 01-13-2012 02:50 PM


sdb sounds like a Physical separate hardrive. Is there 2 hardrives in his computer? Edit: reread your first post. I am not familiar with a

so we had been using the add-on Promise controller, in non-RAID mode. D1 is the boot drive, an SSD, and D0 is a separate hard drive containing all the documents. The boot configuration is now set for D1 to be the boot drive.
So excuse my ignorance.


The second (/dev/sda) is shown as unallocated
This sounds like the 1st hardrive which has not been formatted with any file system yet. Just dead space=eg. unallocated.


/dev/sdb5 ext4 33.85
sdb5 is where Ubuntu is sitting and is the partition that your dad needs to run the check on. It is also the partition Ubuntu should be booting from.


How does one instigate a filesystem check when booting from a Gparted disc?
Image link. Picture is worth a thousand words.
In the Picture. See how unmount is greyed out. That means trhe partition is unmounted and it is safe to do the check. If not greyed out. He needs to hit that first to unmount the partition first. Then proceed to do the check.

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