Re: [gentoo-user] Trying to loopback mount partition from a disk image

[Volker Armin Hemmann]

On Montag 23 November 2009, Stroller wrote:
> Hi there,
>
> With reference to a couple of previous threads:
>    http://thread.gmane.org/gmane.linux.gentoo.user/193263
>    http://thread.gmane.org/gmane.linux.gentoo.user/197120
>
> Here's what I'm trying:
>
> $ ls -lh sda.dd.img
> -rw-r--r-- 1 stroller users 77G 2009-11-22 03:51 sda.dd.img
> $ file sda.dd.img
> sda.dd.img: x86 boot sector, Microsoft Windows XP MBR, Serial
> 0x1890189; partition 1: ID=0x7, active, starthead 1, startsector 63,
> 160810587 sectors, code offset 0xc0
> $ parted sda.dd.img p
> WARNING: You are not superuser.  Watch out for permissions.
> Model:  (file)
> Disk /path/to/sda.dd.img: 82.3GB
> Sector size (logical/physical): 512B/512B
> Partition Table: msdos
>
> Number  Start   End     Size    Type     File system  Flags
>   1      32.3kB  82.3GB  82.3GB  primary  ntfs         boot
>
> $ fdisk -l sda.dd.img
> You must set cylinders.
> You can do this from the extra functions menu.
>
> Disk sda.dd.img: 0 MB, 0 bytes
> 255 heads, 63 sectors/track, 0 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x01890189
>
>       Device Boot      Start         End      Blocks   Id  System
> sda.dd.img1   *           1       10010    80405293+   7  HPFS/NTFS
> Partition 1 has different physical/logical endings:
>       phys=(1023, 254, 63) logical=(10009, 254, 63)
> $
> $ sudo losetup -o 8225280 /dev/loop0 sda.dd.img
> $ sudo mount -v /dev/loop0 /mnt/floppy/
> mount: you didn't specify a filesystem type for /dev/loop0
>         I will try all types mentioned in /etc/filesystems or /proc/
> filesystems
> Trying #
> Trying #vfat
> Trying fuseblk
> mount: you must specify the filesystem type
> $
>
>
> If I format a USB stick as NTFS I can mount and read it fine, so NTFS
> driver modules are correctly compiled into the kernel.
>
> I can `losetup` to a loop device and then `fdisk -l` or `parted /dev/
> loop0 p` and see the partitions.
>
> I've tried with an offset of 512 bytes instead of 8225280 with the
> same results - I guess I'm getting a little confused about what the
> correct offset should be. Thinking about this now it seems "obvious"
> that 512 should be correct, but anyway, that isn't working.
>
> I get the same as Pat trying this:
>  http://article.gmane.org/gmane.linux.gentoo.user/197123
>
> But:
>
> $ sudo losetup -d /dev/loop0
> $ sudo losetup  /dev/loop0 sda.dd.img
> $ sudo fdisk -l  /dev/loop0
>
> Disk /dev/loop0: 82.3 GB, 82348277760 bytes
> 255 heads, 63 sectors/track, 10011 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x01890189
>
>        Device Boot      Start         End      Blocks   Id  System
> /dev/loop0p1   *           1       10010    80405293+   7  HPFS/NTFS
> $
>
> /dev/loop0p1 seems inaccessible to me.
>
> Really, any suggestions on how to access this "virtual partition"
> would be great. Oh, I've also tried to run ntfsclone on it, because
> that can produce images which can be loopback mounted (as per `man
> ntfsclone`) but again, ntfsclone need to be pointed at a partition of
> a hard-drive in order to produce the loopback-mountable image in the
> first place.
>
> Any thoughts?
>
> Stroller.
>

yeah, you don't need to use losetup. I mounted a lot of images over the years 
and I never used losetup.