I wonder how they recovered data from a drive overwritten with 0's. I always use random overwrite myself though. Hard drive data wiping has got to be the most controversial subject of computer forensics. You can literally find citations for everything from no number of passes is ever enough to a single pass with 0's is enough. From what I can gather, the people who sound the most educated on the matter claim that a single pass with random data is enough, and an off track pass could possibly help as well (although that claim is controversial as well). Personally, I feel very safe to do a Secure Erase wipe (which does one on track and one off track pass) followed by a one pass wipe with something like DBAN using random data (in case there is an implementation flaw in the Secure Erase, or something else goes wrong with).