2002-11-18 10:01:05

by Filipau, Ihar

[permalink] [raw]
Subject: useless image of hdd: how to make it useful?

Hello All!

[ please CC me - I'm not subscribed to the list. ]

This question was in my mind for couple of years.
But after all I decided to ask it. (Better later - than never ;-))

Little prehistory: I had on my old home PC two hard drives - hda &
hdc.
hda was big and new, while hdc was old, small and sure it
contained
a lot of old useful stuff. So I decided to upgrade my very
valuable hdc.
And sure, as simple novice in hdd upgrades, I've made smth
like:
# dd if=/dev/hdc of=/root/hdc_img
And right after upgrade - I got small rebate in exchange for
my old hdd -
I understood my problem.

I do not know the way to mount partition table!
it's possible with loop device to mount partition - but how to mount
whole
hdd (with its own partition table) to have access to single
partition inside???

Digging into the kernel (it was 2.2 times) brought no answer:
major+minor was
used to identify the partition and I saw no way I can give this
beast
a file - not real hard drive.

So that's the question:

Is it possible to mount a 'hard drive' - just like any other fs -
and see
inside of this fs partitions as regular files?

PS As for my hdc - very quickly I came back to the shop and reversed my
/upgrade/... ;-)))

--- Regards&Wishes! With respect Ihar "Philips" Filipau AKA Igor Philippov,
and Phil for friends

- - - - - - - - - - - - - - - - - - - - - - - - -
MCS/Mathematician - System Programmer
Ihar Filipau
Software entwickler @ SUSS MicroTec Test Systems GmbH,
S?ss-Strasse 1, D-01561 Sacka (bei Dresden)
e-mail: [email protected] tel: +49-(0)-352-4073-327
fax: +49-(0)-352-4073-700 web: http://www.suss.com/


2002-11-18 20:45:56

by Bill Davidsen

[permalink] [raw]
Subject: Re: useless image of hdd: how to make it useful?

On Mon, 18 Nov 2002, Filipau, Ihar wrote:

> Hello All!
>
> [ please CC me - I'm not subscribed to the list. ]
>
> This question was in my mind for couple of years.
> But after all I decided to ask it. (Better later - than never ;-))
>
> Little prehistory: I had on my old home PC two hard drives - hda &
> hdc.
> hda was big and new, while hdc was old, small and sure it
> contained
> a lot of old useful stuff. So I decided to upgrade my very
> valuable hdc.
> And sure, as simple novice in hdd upgrades, I've made smth
> like:
> # dd if=/dev/hdc of=/root/hdc_img
> And right after upgrade - I got small rebate in exchange for
> my old hdd -
> I understood my problem.
>
> I do not know the way to mount partition table!
> it's possible with loop device to mount partition - but how to mount
> whole
> hdd (with its own partition table) to have access to single
> partition inside???

I believe that you can do it with a network block device, at least in
theory. I lack the inclination to try it, but I'd love to hear that this
suggestion was useful.

You can probably do it with loopback mount and offset, but if I had the
problem I'd try NBD just to see if you really can do it!

--
bill davidsen <[email protected]>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

2002-11-18 21:44:59

by Andries Brouwer

[permalink] [raw]
Subject: Re: useless image of hdd: how to make it useful?

On Mon, Nov 18, 2002 at 11:08:10AM +0100, Filipau, Ihar wrote:

> # dd if=/dev/hdc of=/root/hdc_img
>
> I do not know the way to mount partition table!
> it's possible with loop device to mount partition - but how
> to mount whole hddd (with its own partition table) to have
> access to single partition inside???

loop knows about an offset:

First find where your partitions are:

% sfdisk -l -uS hdc_img
Warning: hdc_img is not a block device
Disk hdc_img: cannot get size
Disk hdc_img: cannot get geometry

Disk hdc_img: 0 cylinders, 0 heads, 0 sectors/track

Units = sectors of 512 bytes, counting from 0

Device Boot Start End #sectors Id System
hdc_img1 63 112454 112392 83 Linux
hdc_img2 112455 401624 289170 82 Linux swap
hdc_img3 401625 33736499 33334875 5 Extended
...

OK, let us mount this first one, at an offset of 63 sectors.

% bc
63*512
32256

# mount hdc_img /mnt -o loop,offset=32256
#



2002-11-21 20:34:21

by Bill Davidsen

[permalink] [raw]
Subject: Re: useless image of hdd: how to make it useful?

On Mon, 18 Nov 2002, Andries Brouwer wrote:

> Device Boot Start End #sectors Id System
> hdc_img1 63 112454 112392 83 Linux
> hdc_img2 112455 401624 289170 82 Linux swap
> hdc_img3 401625 33736499 33334875 5 Extended
> ...
>
> OK, let us mount this first one, at an offset of 63 sectors.
>
> % bc
> 63*512
> 32256
>
> # mount hdc_img /mnt -o loop,offset=32256
> #

Being at heart a lazy fellow, and not counting on people to have bc
installed although they should...
# mount hdc_img /mnt -o loop,offset=$[63*512]

--
bill davidsen <[email protected]>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.