Apple - Securely erase all user data on an old iBook

You can use the Disk Utility program supplied by Apple - and you can tell it how many overwrites you wish it to do, the last time I read that info it said one pass was not very reliable, 7 should be fine and 35 was overkill - bear in mind how long it takes to do one complete pass....

A similar question is here : Selling a Macbook Pro - removing personal information from it

Edit: You need to boot from a different media as it cannot work on itself so, either the original install disc or a newer install disk for a later version - as older ones don’t usually work forwards... Other bootable media may also work - but that I have not tried...

You need to boot the iBook from supported boot media (like a compatible or retail PPC Mac OS X installer CD or DVD) to do this. Another way is using PPC compatible Linux, but an older version for the G4 CPU. Ubuntu 9.x is a good candidate, as is YellowDog Linux. Gentoo is known to have a working ISO image, ready to burn, but that probably is harder to track down. Booting from USB was not really supported, some OpenFirmware versions did make it available, but it was flaky at best. Machines that were the most reliable regarding USB boot were the G5 Towers and G5 iMacs.

Keep in mind that before you do all this you may want to ensure you have the latest firmware updates installed. While there haven't been any updates for a decade, it is still possible that a previous owner has not installed them all, and you can't do it without a Mac OS installation.

For reference, a link to a known working Linux CD ISO image (I have a PPC G4 1.2Ghz white iBook here as well, works with that CD):

This is the 'alternate' image, which should allow you to boot a bit faster on low-memory machines and has a few extra tools to allow you to wipe the disk (I'd suggest just writing zeroes to the whole thing, or if you are paranoid use /dev/urandom and write that to the /dev/hda or /dev/sda). When it boots, you can just ignore the installer and move directly to 'recovery shell' to get going.

Use srm (secure removal of files/directories) to securely delete the User folder with your personal data.

srm has been in OS X since 2004 so it's included with Tiger. This will allow you to securely delete your files without affecting the rest of the OS. This has the added advantage of whomever you're donating to doesn't have to go through the trouble of finding install media to get the machine working again.

  1. Boot your iBook
  2. Create a new user with Admin priviliges
  3. Log out and log back in as the user you just created
  4. Open Terminal
  5. Navigate to the the /Users folder
  6. Issue the command srm -rf [Username]
  7. Close Terminal
  8. Go into System Preferences >> Users & Groups
  9. Delete the old user

That's it... Your personal data is gone and you don't have to go though any convoluted steps to boot Linux.

As for srm and the level of security, you can add the following flags:

  • -s = simple; overwrite with a single pass of random data
  • -m = medium; overwrite with 7 DoD compliant passes
  • -z = zero; after overwriting, zero the blocks used by the file

You can get more info on srm from the man page (man srm)