drive recovery of dual-boot system

[Mike Bilow]

Filesystems (and therefore "fsck" targets) reside on partitions of the 
disk, something like "/dev/sdc3", rather than the entire device (or an 
image of it). This is inherent in the design of the system and is 
independent of the types of filesystems or how they are mixed.

In order to access partitions within an image file, you want the 
"kpartx" utility:

     http://linux.die.net/man/8/kpartx

Also, those annoying Dell machines that will not boot from CD will boot 
from USB Flash memory, and it is easy to make one up with SysRescueCD:

     
http://www.sysresccd.org/Sysresccd-manual-en_How_to_install_SystemRescueCd_on_an_USB-stick

-- Mike


On 2012-01-26 00:47, Greg Rundlett (freephile) wrote:
> I have an internal hard drive that won't boot.
>
> The system (Dell Studio Hybrid) also will not boot from CD-ROM 
> (regardless of what I do with the boot sequence, F2, BIOS settings 
> etc.)  In fact it doesn't seem that BIOS settings actually get saved. 
>  But that's another matter.  I'm concerned with recovering data from 
> the failed drive.  And obviously using a bootable CD like the System 
> Rescue CD won't work.
>
> I bought an enclosure so that I could read from the drive using my 
> laptop as the working host.
>
> The bad drive in question is 250GB and has a number of partitions and 
> file system types:
>
> Disk /dev/sdc: 250.1 GB, 250059350016 bytes
> 255 heads, 63 sectors/track, 30401 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x50000000
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1               1           7       56196   de  Dell Utility
> /dev/sdc2               8        1966    15728640    7  HPFS/NTFS
> /dev/sdc3   *        1966        5881    31453961    7  HPFS/NTFS
> /dev/sdc4            5882       30401   196956900    5  Extended
> /dev/sdc5            5882       29402   188932401   83  Linux
> /dev/sdc6           29403       30401     8024436   82  Linux swap / 
> Solaris
>
> At first I tried dd_rescue to copy the entire device to a file on an 
> external 1TB drive.  The device is a dual-boot setup so it has a 
> Windows partition and a Linux partition (plus factory-installed 
> recovery and utility partitions).  dd_rescue copied a lot of data but 
> it complained when I ran fsck on the resulting file:
>
> # fsck -y /media/disk-a/backups/hybrid/backup.img
>
>     fsck from util-linux-ng 2.17.2
>     e2fsck 1.41.11 (14-Mar-2010)
>     fsck.ext2: Superblock invalid, trying backup blocks...
>     fsck.ext2: Bad magic number in super-block while trying to open
>     /media/disk-a/backups/hybrid/backup.img
>
>     The superblock could not be read or does not describe a correct ext2
>     filesystem.  If the device is valid and it really contains an ext2
>     filesystem (and not swap or ufs or something else), then the
>     superblock
>     is corrupt, and you might try running e2fsck with an alternate
>     superblock:
>         e2fsck -b 8193 <device>
>
>
> This leads me to think that I can't create a backup of the entire 
> device to a single file if the device is partitioned into multiple 
> file system types.  So, I'm back to square one.  I'm going to try gnu 
> *ddrescue *and create a copy of just the Linux partition into a file 
> on the external USB drive.  Then I'll try mounting that file as a loop 
> device to see if I have my data.
>
> Is my understanding correct, or should I be able to backup the entire, 
> multi-filesystem, multi-partition device.  In the latter case, I was 
> going to restore it to a new drive (still in the mail) and hope that 
> I'd still be able to dual-boot the system.  If I can only do one OS at 
> a time, then I'm hoping I won't run into problems trying to install my 
> licensed copy of windows onto a new hard drive from media that I don't 
> have.
>
>
> Greg Rundlett
> my public PGP key 
> <http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x5E07A26B877CEBF6>