accurately dd sectors?

_______0 · Guru Joined: 15 Oct 2012 Posts: 521

hi,

With fdisk I have a layout that the last partition ends in 1465147119 but fdisk reports total of 1465149168. This is confirmed with GUI gparted that shows a piece of un-allocated section at the end. Either m$$ install is bugged or does it to prevent damaged?

How to accurately dd that space in order to examine it? I find it funny that m$$$ doesn't use 100% of hard drive.

BradN · Posted: Sat Jun 08, 2013 7:57 pm Post subject:

The partition probably doesn't start at the beginning of the drive. If it did start at the beginning there would probably be something wrong, as this isn't usually allowed because the partition table shouldn't be part of a partition.

You need to examine: First sector, count of sectors

This tells you where a partition is. Make sure you do your math right so you don't get an off-by-one error: If you add count_of_sectors to first_sector, you will arrive at the sector number for the first sector AFTER the partition.

My trick for these things is always construct a simple test in your head - first sector is 1, number of sectors 1... if you add them you get 2 which is after sector 1 (the only one in our pretend partition).

_______0 · Guru Joined: 15 Oct 2012 Posts: 521

I am not getting you. The un-allocated part is at the very end of the disk drive:

from

1465147119

to

1465149168

mm.. I just realize that it isn't a partition so I don't know how to use dd in this case. This is similar than copying the mbr part.

can u help? :/

ulenrich · Veteran Joined: 10 Oct 2010 Posts: 1480

gpt patition tables do have a backup at end of disk!
Let it live there!