bit-for-bit disk copy using dd?

Hi,

I'm trying to use "dd" to copy one HD to another.

The original is an old W95 disk, 1.7 GB and the destination
is a blank 3 GB disk.  I do (booting from install disk
floppies and dropping to a prompt):

$ dd if=/dev/rwd0d of=/dev/rwd1d  and wait 1,769 seconds and
then it finishes.

But when I do this, the copy doesn't boot when I move it to
the destination system; it's as if there's no OS.

The original disk boots just fine.

So, is there some extra-special secret sauce needed to make
a "clone" of a disk with dd?

Thanks -Mike

Hmmmm, seek and ye shall find...

I was able to use a smaller disk as my destination, a 2.2
Gig 2.5" drive.... And this worked!

I don't understand why this didn't work for even slightly
larger disks, but, anyway, the "dd" command, as
below, does seem to make a bit-for-bit disk copy.

-Mike


On Mon, 11 Jun 2007, Mike Cheponis wrote:

> Date: Mon, 11 Jun 2007 17:34:29 -0700 (PDT)
> From: Mike Cheponis <macWireless.Com>
> To: netbsd-helpNetBSD.org
> Subject: bit-for-bit disk copy using dd?
> 
> Hi,
>
> I'm trying to use "dd" to copy one HD to
another.
>
> The original is an old W95 disk, 1.7 GB and the
destination is a blank 3 GB 
> disk.  I do (booting from install disk floppies and
dropping to a prompt):
>
> $ dd if=/dev/rwd0d of=/dev/rwd1d  and wait 1,769
seconds and then it 
> finishes.
>
> But when I do this, the copy doesn't boot when I move
it to the destination 
> system; it's as if there's no OS.
>
> The original disk boots just fine.
>
> So, is there some extra-special secret sauce needed to
make a "clone" of a 
> disk with dd?
>
> Thanks -Mike
>

Also sprach Mike Cheponis (macWireless.Com)
> Hmmmm, seek and ye shall find...
> 
> I was able to use a smaller disk as my destination, a
2.2 Gig 2.5" 
> drive.... And this worked!
> 
> I don't understand why this didn't work for even
slightly larger disks, 
> but, anyway, the "dd" command, as below, does
seem to make a bit-for-bit 
> disk copy.

If you are copying Windows it might be a Windows problem.
They
hardcode some HDD-data into the boot process, that breaks
when the HDD
changes. 

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