erasing drives and sleeping well at night

You need to start up from the Mac OS X installation disc (insert disc and start up with the C key held down), if you are trying to erase the internal drive. Run Disk Utility from the Installer screen, by going up to the menu bar and selecting to run Disk Utility under the Utilities menu.

In the sidebar, select the DRIVE (not the volume indented under the drive). Go to the Erase tab. Click +Security Options+. Select to do a +Zero Out Data+ erase. This will write zeros to all drive sectors, making your existing data unrecoverable to practical purposes. Note: This process can take some time, depending on the size of the drive.

When it completes, quit Disk Utility to go back to Installer. Have Installer run the default installation. After it finishes, it should start up from the new installation. Quit the setup utility and shut down. When the new user starts up for the first time, he or she should be prompted to go through the setup screens.

My nephew works at a data recovery center. He claims even the highest Mac security setting (35 zero out passes) is NOT fully secure. Only TOTAL destruction of disk is foolproof. And that means TOTAL destruction. Fragments can contain recoverable data.

35 passes is 34 passes more than the average bear needs to worry about. It depends on your level of paranoia and what you want forever hidden. If your material is REALLY sensitive...remove the drive.