How to REALLY erase a hard drive by Robin Harris
Who Knew? Turns out there is a way to do a full erase on a hard drive already built into the firmware on the drive.
So what’s the magic?
Something called Secure Erase, a set of commands embedded in most ATA drives built since 2001. If this is so wonderful, why haven’t you heard of it before? Because it’s been disabled by most motherboard BIOSes.
Secure Erase is a loaded gun aimed right at all your data. And Murphy’s Law is still in force. But hey, if you’re smart enough to read Storage Bits, you’re smart enough to not play with Secure Erase until you need to.
I use Boot ‘N Nuke myself, which he also mentions.