Q: Erasing everything

Hi Jaycee56, and a warm welcome to the forums!

1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*
3. Click the Erase tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Highlight the drive, select Partition Tab, then Format type... MacOS Extended Journalled, select the Security Options button, choose Zero Out Data, Erase... You'll have choices of Once, 7 times, or 35 times, (which will take a week or so depending on the drive size).

Zeroing out the data is the essential ingredient.

One pass makes your data almost completely unavailable without special lab equipment and weeks of work. This is suitable for all but Nuclear secrets.

Good news, & good luck on the sale!

I discovered some things on the Web regarding bad sectors on hard drives, and information stored there. Is anyone familiar with the below methods?

The below link mentions the additional issue of data that is found in bad sectors of the hard drive:

[http://advosys.ca/viewpoints/2006/07/hard-drive-secure-erase>

If one has access to a computer with Windows on it, apparently one can securely erase those bad sectors with a program that can be downloaded via a link at the following web page:

[http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml]

There is another program, which is available for Linux and Windows, called hdparm, which can also apparently be used to erase those bad sectors:

[https://ata.wiki.kernel.org/index.php/ATASecureErase]

[http://en.wikipedia.org/wiki/Hdparm]

The steps appear to be somewhat involved, and they include "unfreezing" the hard drive. The web page at the below link has some recommendations with regard to unfreezing the drive:

[http://forums.macrumors.com/showthread.php?t=841182]

One of the suggestions involves putting the hard drive in an external enclosure, and connecting it via a USB cable to a computer running Linux. Also, if I understand correctly, if one's hard drive is the only drive on the machine, one would need to boot the computer from some sort of bootable medium that has the hdparm utility on it (such as, for example, a bootable Linux CD). Alternatively, one could connect the drive via the aforementioned USB cable to a second computer with Linux or Windows on it, in order to unfreeze the drive and then run the hdparm utility.

Having not yet erased a hard drive by any of the above means myself, any insights regarding them would be greatly appreciated.

Ordinary folks, even those who have recently been through an ugly divorce, can wipe their data once with write zeroes and be done with it.

If your old data are so sensitive that the possible "unreadable" bad data in spared blocks is a potential issue, a Hammer is the recommended disk wiping tool of choice.

Thank you for sharing the insights, Grant and Jaycee56.