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Re: Installing the MBR on a new Hard Drive



On 26/04/12 10:02 AM, Martin McCormick wrote:
	I have made a copy of the / file system from the boot
drive on a Debian Squeeze system to a new flash drive as the
original drive is about 13 years old, works fine, but I don't
want to push my luck too far. I used fdisk to format the new
drive, made Partition 1 bootable and then used rsync to copy all
the files one can from the old drive to the new one.

	It came time to install a MBR on the new drive so I
found some instructions which raise a question.

	I know you are supposed to copy the image of a boot
floppy to the first 446 bytes of the new drive which is what I
did. This is done by

#   dd if=/dev/hda of=/dev/sdb bs=446 count=1

	It appears to have worked but I have not yet installed
the drive in the system and booted from it but there was also an
alternative instruction:

#   dd if=/dev/hda of=/dev/sdb bs=512 count=2

	What, besides the obvious fact that one is copying more
bytes, is the difference between copying just the MBR and
copying the 1024 bytes?

	Was this even necessary since I had already made
fdisk set Partition 1 bootable before doing mkfs?

	For anybody interested in doing this, make sure you know
your drive device designations as they will be different than
what I used in this example and you could really mess up your
day if you don't be careful.

Martin McCormick


Personally, I'd just dd the entire old disk to the new one. Then use gparted (from a live distro) to resize your partitions.

However, since you have already done it differently, you don't need to dd the mbr. Instead, install grub on the new drive (again, boot from a live distro). Create a chroot environment for your new / partition and install grub from it.


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