Re: Wiping a drive: /dev/zero or /dev/urandom better?

["Eric Kollmann" <xnih13 () gmail com>]

> And once is enough. Multiple passes are not much use.

I believe this is the original study from 1996 timeframe that got the
whole issue of multiple passes started up:
http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html

Just so people have some background on why "once is enough" today,
here is one study (others may argue differently):
http://csrc.nist.gov/publications/nistpubs/800-88/NISTSP800-88_rev1.pdf

A few quotes from the above publication:
p.6:
"That is, for ATA disk drives manufactured after 2001 (over 15 GB)
clearing by overwriting the media once is adequate to protect the
media from both keyboard and laboratory attack."

p.8:
"Studies have shown that most of today's media can be effectively
cleared by one overwrite."

Your need to go beyond one wipe is up to you, but due to disk density,
one wipe is/should clear the data according to this 2006 study by NIST
(on ATA drives at least).