dd produced wrong output

[meierfra]

Binary package hint: coreutils

I used dd ( coreutils 6.10.6ubuntu1, Ubuntu 8.10, Release 8.10) to look at the last sector of the ntfs partition on my external hard drive:

sudo dd if=/dev/sdb1 skip=142464419 of=last_sector count=1

This last sector is supposed to be the backup boot sector, but the binary file last_sector only contained zeros.

 I booted from a Knoppix CD (coreutils 5.97) and the same command produced a file which did indeed contained the boot sector of the ntfs partition.

I then looked at the same sector from Ubuntu 8.10 via

sudo dd if=/dev/sdb of=last_sector skip=167043869 count=1

and last_sector contained the boot_sector

I repeated the first command from a second Ubuntu 8.10 on my external hard drive, and again got nothing but zeros.

I also did

sudo dd if=/dev/sdb1 skip=142464415 of=last_sector1 count=5

and

sudo dd if=/dev/sdb of=last_sector2 skip=167043865 count=5

from Ubuntu 8.10 and the first sector in the two files were identical, but the last four sectors in the first file had nothing but zeroes, while the second file ended correctly in the boot sector.

So this seems to be a bug in the coreutils 6.10.6ubuntu1 package.