Zeroing Hard Drives
Have a couple of old Hard Drives that I want to dispose of. So, using my Mac's disc utilities I see I have four options:
1. Erases just the File allocation information. Data could be gotten to by just about anyone (and their dog)
2. Writes, in one pass, a zero over every bit of the disk.
3. Writes, in a few passes, zeros etc.
4. Meets DoD specifications and writes zeros seven times (etc.)
Obviously number 1 isn't what I want.
But what is the difference between Number 2 and Number 4. Why would seven passes be better than one. A zero is a zero - my data should be nuked.
The difference in time for a 150gb disk is about six hours.
Do I really need to leave this overnight ???