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.

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.

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.

If me. I would try

https://help.ubuntu.com/community/Sy...istration/Fsck

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

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.

http://distrowatch.com/table.php?dis...on=partedmagic

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

http://ubuntuforums.org/showthread.php?t=1601810&page=2

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

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.

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?

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.

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)?

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.

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

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

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!

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 excuse my ignorance.



This sounds like the 1st hardrive which has not been formatted with any file system yet. Just dead space=eg. unallocated.

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.

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.

Thank you very much. Yes, one hard drive has the documents, etc., and one has Ubuntu. The documents drive (an HDD) is mounted to /home, whereas the other drive, mounted to /, is an SSD. I cannot remember which way around that that they are, but neither drive should be unallocated - both should have ext4 filesystems, one with the operating system, the other with documents.

If /dev/sda is the documents hard drive that has gone wrong somehow, and it is set to be mounted to /home, would that possibly cause the system to fail to boot in the way described? Do you have any idea how a previously functioning hard drive might suddenly start to show as unallocated in the circumstances described?

In any event, I shall instruct my father how to run the test and see whether anything turns up.

Not being familiar with a add-on Promise controller, in non-RAID mode. All I can guess is somehow the power cut scrambled that controller which may have scrambled the hard drive also. If sda held all the documents and was symlinked to /home on sdb. Your dad or you have your work cut out for you trying to retrieve said documents from a unallocated drive. The parted magic cd comes with test disk tools for situations like this. Google will be your friend on how to recover data using testdisk on sda if I read you right.

I run a APC
Backup on my motorcycle shop and home Desktop PCs to avoid the kind of situation you and your Dad are finding your selves in right now.

Happily, there is a backup to a remote hard drive, which was put in place using Deja Dup. The system needs to be working, however, before the restore can take place, and that will be a somewhat fiddly process. I wonder whether that will be easier or more difficult than the recovery tool that you mentioned?

Thank you, incidentally, very much for your help with this.

The remote backup would be easier if you can get it working/functioning if need be.

Thank you. I think that I shall have to pay my parents a visit to fix their system in person. This is most annoying, since I had only just finished setting up their computers when the power cut struck!

Mention to your Dad about using a APC backup power supply like I mentioned. It will save both of you major grief later IMO

Ahh, thank you - will consider that.