DdAa wrote:
Can anyone tell me what level of security is secure delete? (I mean securely emptying the trash.)
It's a 7 pass erase approved by the Department of Defense and the NSA for hard drives.
Since it's usually done for small files, it doesn't take a long time, however if you use Disk Utility > Erase Free Space and use the 7x pass, it can take quite a long time, days even.
The Erase Free Space > Zero is a one pass and designed to stop software like Data Rescue from reading the deleted bits that are due for a overwrite if more data comes along to be written.
If your selling the machine, you can Zero bit erase the entire partition or drive and reinstall OS X brand new with the video and everything.
How do I securely delete data from the machine?
How to erase and install Snow Leopard 10.6
Erase, formatting, OS X installs on Mac's