Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

I have a desktop with a dual boot, Windows XP, which I hardly ever use, and Ubuntu. Ubuntu failed me and had a back square on the right-hand top, and after lots of forums and no luck to resolve it, I decided to reinstall Ubuntu via a live CD. No such luck, as I am now can not even boot XP, and get a message:

error: unknown filesystem
grub rescue>

I have done this three times now, and still get the same message. During the process I instructed to unmount. I hope that did not stuff things up. Anyone out there who can help through this? I am not very highly skilled though and would need patience and exact instructions.

sudo fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x87de87de

Device Boot Start End Blocks Id System
/dev/sda1 * 63 156296384 78148161 c W95 FAT32 (LBA)


Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x963f963f

Device Boot Start End Blocks Id System
/dev/sdb1 * 63 293760044 146879991 7 HPFS/NTFS/exFAT
/dev/sdb2 293761022 976773119 341506049 5 Extended
/dev/sdb5 964902912 976773119 5935104 82 Linux swap / Solaris
/dev/sdb6 293761024 964902911 335570944 83 Linux

Partition table entries are not in disk order


Disk /dev/sdc: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders, total 1250263728 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc048ea69

Device Boot Start End Blocks Id System
/dev/sdc1 63 1250258624 625129281 7 HPFS/NTFS/exFAT


Disk /dev/sdd: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0009f1e3

Device Boot Start End Blocks Id System
/dev/sdd1 2048 237579626 118788789+ 83 Linux
/dev/sdd2 237580286 488396799 125408257 5 Extended
/dev/sdd5 468523008 488396799 9936896 82 Linux swap / Solaris
/dev/sdd6 237580288 468523007 115471360 83 Linux

Partition table entries are not in disk order

I am not sure which partition it is in...is that bad?:! I am not sure which disc ubuntu is on. I am not sure if I edit my comments here? Avinash Raj suggests to try boot repair...I have no idea how to that either.

I ran the boot repair and got a lot of data, which I tried to copy here via my laptop, but it comes up with a message "you need at least 10 reputation to post more then 2 links. and it will not send the info here is part of it

ubuntu@ubuntu:~$ sudo add-apt-repository ppa:yannubuntu/boot-repair &&sudo apt-get update
You are about to add the following PPA to your system:
 Simple tool to repair frequent boot problems.

W: Duplicate sources.list entry cdrom://Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)/ precise/main i386 Packages (/var/lib/apt/lists/Ubuntu%2012.04.2%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20130213)_dists_precise_main_binary-i386_Packages)

W: Duplicate sources.list entry cdrom://Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)/ precise/restricted i386 Packages (/var/lib/apt/lists/Ubuntu%2012.04.2%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20130213)_dists_precise_restricted_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
ubuntu@ubuntu:~$ 

how do I create a link-to post it as a comment? I think I am getting totally confused here. first is THIS HERE the right spot to post my answers? because i can not see it in the thread once I "save my edits" how do I creat a link to post it as a comment? and what commands do i put in where? please be patient and so not give up on me:)

no, I do not it stays on the terminal and I get this

ubuntu@ubuntu:~$ boot-repair: command not found
boot-repair &
[2] 7800
[1]   Exit 127                boot-repair
ubuntu@ubuntu:~$ boot-repair: command not found
[1]+  Exit 127                boot-repair

have been at it all day and have a huge head ache. thanks for all your help, I will need to go to bed now,but I will come back :):):) I get now boot repair window. but:

command not found exit 127 \boot repair

share|improve this question
    
I am running a life cd of ubuntu 12.3 –  kalhandra Jan 23 at 1:27
    
:) You can edit the question, add info there. So you have 4 disks. Do you know which one you have installed Ubuntu in? –  Sneetsher Jan 23 at 2:31
    
try boot repair,if not works then post it's log. –  Avinash Raj Jan 23 at 2:50
    
try the 2nd option in help.ubuntu.com/community/Boot-Repair –  Avinash Raj Jan 23 at 3:05
    
@user238456 You need to scroll to the original post at the top and edit the original question. See this image for a reference. –  minerz029 Jan 23 at 3:30

1 Answer 1

As @Sneetsher pointed out, the answer to your title question is to try mount and exam one by one when boot from a live CD. The following would just be something to a more manual boot repairing, if helpful :) (the length doesn't fit in the comment)

BIOS -> MBR -> bootstrap loader -> kernel -> os

first of all, be sure which is 'bootable device'. usually BIOS picks up the first device. so normally the installer will also try to install MBR there, can be changed though.

second, the MBR in the booting device, read bootsector & loads the bootstrap loader in the 'active partition'. from your disk partition list, the one with '*' symbol found is the 'active partition'. (/dev/sda1, /dev/sdb1).

third, the kernel image, this can be chainloaded from second step, specially when the bootstrap loader is GRUB.

assume your Ubuntu is installed in /dev/sdb, from the partition table, it is a big possibility there's only '/' filesystem mounted on /dev/sdb6. then you could boot from live cd, and then try 'grub-install'. read 'man grub-install', that's how lots of users survived, as long as the concept is clear.

hope this helps

share|improve this answer
    
You are right! but @user238456 seems new to such thing. (This was 1st time he launch terminal), my question Do you know which one you have installed Ubuntu in? Answer: No was just to confirm. That's why I avoid such path. Concerning Ubuntu root partition we can check by mounting all expected Linux partition and see theirs root folder. –  Sneetsher Jan 24 at 9:46
    
thanks for pointing out. :) updated the contents. i never used boot-repair though. general purposed tools sometimes add more problems specially when it's magical. –  timl Jan 28 at 3:16

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.