Formatting a disk

[Antony Gelberg]

Daniel Carrera wrote:
> Hello,
> 
> I did this:  dd if=/dev/hda of=/dev/hdb count=1 bs=512
> 
> I was expecting this to copy the MBR, which it probably did. But it also
> made fdisk not understand the disk:
> 
> # fdisk /dev/hdb
> The number of cylinders for this disk is ... There is nothing wrong with
> that but it is larger than 1024 and could ... cause problems...
> 
> Unable to seek on /dev/hdb

This /sounds like/ a hardware error to me and not necessarily a broken
MBR.  However, who knows what happened at driver level?  You should be
able to access the partition table whatever the MBR looks like.  They
are two separate entities.

Are the two disks identical?  Do cfdisk and sfdisk produce the same results?

> #
> 
> So, fdisk barfs on /dev/hdb.
> 
> Does anyone have a rescue suggestion? (yes, I should have done a backup
> of hdb's MBR but I didn't). There must be a tool that can bring sanity
> to a disk with a broken MBR.
> 
> Btw, yes, fdisk did work before the dd command.
> 
> Btw, if I can't copy the MBR from one disk to another I don't see how
> I'll be able to install Ubuntu OEM images on many disks.
> 
> Cheers,
> Daniel.