[ILUG] harddisk swap

[Enda]

Timothy Murphy wrote:
> On Thursday 29 April 2004 17:52, Enda wrote:
>
> >> I would be very surprised if you could copy the MBR in this way.
>
>> Its perfectly valid to copy the MBR in this way, but the values will
>> probably be wrong. If its a lilo boot loader, you'll need to edit the old
>> /etc/lilo.conf and point the moutn points to the scsi instead of the ide,
>> and write it to the MBR using lilo -C path_to_edited_lilo.conf
>
> What is the point of copying the MBR
> if you then use LILO or grub-install to write it out again?

None. Well done sherlock. If he replaces the disk with another IDE disk,
with the same partition structure as the original, then there is every
point, as it will yield him a booting system without any re-configuration.
As I say, a perfectly valid operation to do.

> IMO there is zero probability of an MBR from one disk working on another,
> so as I said it seems entirely pointless to copy it.

Says more about your opinion than it does about how the MBR works.

There is no "voodoo" involved. MBR merely contains minimalist code that the
minimalist bios is able to load, to take the boot process further.
Capabilities of code in the MBR are constrained by what the bios can load.
MBR, be it a windows or linux MBR, tells the bios where to find the kernel.
Where the drive class is the same, ie, SCSI / IDE etc, the device labels are
the same, and with partition schemes been suggested identially out of the
box, the probability of swapping MBR's and them working is very very high.

Even in the case where you are the admin, and you manage to screw the
"standards" up, as long as you do it consistently, you'll have a ball.

 -Enda.