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sunrain
Veteran Member
 
Join Date: Jun 2004
Location: Portlandia
 
2005-05-09, 13:51

Wiping your computer for resale by sunrain

This is for folks that are selling their old computer and want to have their data safe from harvesting and at the same time make the computer ready for its new owner. After making extra sure you've got any data you want off of the computer, there are really two main steps.
  • Format the hard drive (various options)
  • Re-install the operating system


1. Format the hard drive:

Your most basic method of formatting the hard drive is to use your install discs and select the Erase and Install option and skip down to the 're-install' step. If you're not the slightest bit worried about your data, or don't care, this is your easy option.

The next formatting options are a bit more involved and easiest* done with two computers; both with Firewire ports. These options provide much more security from data harvesting. You'll be using one computer (the controlling computer) to wipe the hard drive of the other (target computer) using 'Target Disk Mode." This mode basically turns the computer into a large hard drive and is accessible like any external drive.

Restart the 'target' computer you want to reformat and press 'T' during startup to enter into this mode. You'll know when it has worked when you see a Firewire symbol on the screen. Make sure your 'controlling' computer is booted up. Plug the Firewire cable into this computer first and then into the 'target' computer. The 'target' computer should then mount as a hard drive on the desktop of the 'controlling' computer.

*Note: You can also use your Disk Utility from your install disc(s).

Open a Finder window on the 'controlling' computer and select Applications>Utilities and open Disk Utility.

Disk Utility lists all the available drives and volumes in a column, on the left-hand side of the window. The drives usually have cryptic names (like "ST380020A") while your volumes are indented and reflect the names you are familiar with and you see in the Finder's Computer window. You should see the mounted 'target' computer drive and volume(s) in the utility along with the 'controlling' computer's hard drive (and volume(s)).

Select the 'target' computer drive and then select the Erase tab and then the Security Options button. The Security Options button allows you to select a hard drive "scrubbing" method that will make your previous data harder to retrieve from your disk. To make it more difficult to recover the files on the disk, you have the option of doing this once, seven times, or 35 times. If you have a large disk, overwriting the free space several times can take a very long time. Select your option, close the Security Options dialog and select erase.

Take a walk, watch a movie and wait for it to finish. Then unmount the 'target' computer from the 'controller' computer and remove the Firewire cable.
Brad's wisdom on the subject:
Quote:
Simple reformatting (Erase and Install) is enough for the casual user. Zero-wiping is good for any educated user. Multiple-pass-wiping is only for the truly paranoid.
2. Re-install the operating system

This is as straightforward as any other Erase and Install, with a slight change towards the end. When the installation process informs you that the installation is finished and will reboot, allow the computer to start the reboot process and then power it off before it reboots (i.e. once you hear the boot sound). This allows you to install the operating system so that the opening 'welcome' movie will come up when the new owner first boots. This allows the new user to create their own account, put in their own preferences, register, etc.

"What a computer is to me is it's the most remarkable tool that we've ever come up with, and it's the equivalent of a bicycle for our minds."
- Steve Jobs
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