hard delete software

Boot off your installation disc by holding down C on boot. You can then access disk utility from the menubar.

Select the drive and then the erase tab and then there will be a security options button, in there you can select different levels one being 7 pass or you can do 35 pass if you really want.

 

It's built into OS X. When formatting a drive through Disc Utility, you can choose to write random data once, seven times (DoD standard), or thirty-five times.

 

Apple's software will do this, and it's built in to your system.

Launch your laptop with the system restore DVDs it came with, then go to the Utilities menu in the menu bar and choose Disk Utility. Choose your hard drive's internal volume, and go to the Erase tab on the right. You can specify the filesystem (Mac OS Extended Journaled is fine), and the volume name. Then click "Security Options..." and choose 7-pass erase. This will take a LONG time, I'd suggest leaving it run overnight, could take as long as 24 hours based on how big your hard drive is.

Really though, it's overkill unless you have LARGE amounts of incredibly secret things on the drive. It makes more sense to simply secure delete those specific things. You can do this by dragging them all to the trash, and then choosing "Secure Empty Trash" from the Apple menu, which overwrites just the areas of your hard drive that were consumed by those files 7 times with random noise. Then you can do a plain format and re-install of the system software to bring the machine back to a clean state.

 

Under the Options on Disk Utility they have the option to do several formats, including a 7 pass format and a 35 pass format. In most cases doing the simple quick erase will work fine, as it destroys the master boot record, however I have seen errors if you don't do it twice, for some reason.

Also, secure empty trash will write '0's over any deleted files, and you always have the option of writing '0's over your free space at any time.

TEG