"Just to clarify, "formatting" a drive is not good enough. It needs to be *wiped*, i.e. random data or zeros need to be written across the drive. [One pass is enough](http://en.wikipedia.org/wiki...), with the caveat that if the drive has dynamically remapped a sector due to read errors, [that data may still physically remain on the drive](http://en.wikipedia.org/wiki...). As I stated elsewhere in this thread, flash storage is a whole different animal." - Ryan Steele