How to really erase my hard drive

Problem

I have an old hard drive which I want to throw away, but not before destroying all data on it. How can I really erase all data on this old hard drive, non-recoverable?

Environment

• Ubuntu-10.04
• Hard drive Maxtor 7546 AT, 547MB

Solution

Use the shred utility which is capable of overwriting files repeatedly "... in order to make it harder for even very expensive hardware probing to recover the data" (from: man shred).

Note that overwriting the entire hard drive lasted 48 hours on my machine.
Prefixing the command with screen (or tmux?) allows you to abandon this long-running process:

# NOTE: Replace DEVICENAME with name of device (/dev/xxx) to shred
# You can find out the device name with 'parted' (console) or
# 'partitionmanager' (KDE)
screen sudo shred -v DEVICENAME

Appendix A. Parted

p devices
select DEVICENAME
p