Problem wiping a drive with shred command

[galapogos]

Hi,
I'm trying to wipe an entire 20GB drive with the shred command using Knoppix. Specifically this is the command I'm entering

shred -n 2 -f -v /dev/hda

To my understand from reading the man pages, this writes random data to the drive(/dev/hda) twice, forces permissions, and shows progress.

I see progress up to about 96% for the 1st pass, then I get 2 lines of error at the end of the drive. Something like "error writing to offset x, input/output error", where x is the end of the drive.

The 2nd pass never runs due to this error, the the program terminates back to the shell.

Does anyone know what's wrong?

TIA.

[FoolishGhoul]

you need to unmount the drive first.

code you will need:

sudo umount /dev/hda

shred -n 2 -vf /dev/hda

might not need to sudo if you're already in superuser mode...

[devils casper]

I would suggest you to write zeros in whole harddisk through dd command instead of using shred.

dd if=/dev/zero of=/dev/hda

Or

Use DBAN.

[FoolishGhoul]

yeah, i'd forgotten about that, Darik's Boot and Nuke (DBAN) is an excellent tool for wiping hard-drives of computers, have used it on many i've sold/given away/scrapped...

[galapogos]

I do know about DBAN. In fact it was the first thing I've tried. However, most of DBAN's algorithms do a final zeroization pass, which I don't want. I want the contents of the HDD to be randomized instead. Hence I'm using shred w/o the -z option, and hence I'm not using dd.

Of course, if there is an easy way to disable the final zeroization pass then I'm open to using DBAN.

I will try umount on the drive with shred in the meantime.

[galapogos]

Hmm, the drive doesn't seem to be mounted at all, so umount did nothing. Any other ideas? Could the drive have bad sectors or something? DBAN did complete the wipe though.

[oz]

Hi, galapogos!

If you still need help with this please create a new thread. I'm locking this one because it has attracted 8 different spam messages already.

Sorry for any inconvenience.