Tuesday, August 27, 2013

Securely wiping a classic Mac OS 9 PPC computer

I found an Apple iMac G3 that had been in my basement for 15+ years! It has 64mb of RAM which was enough to run the apps of 1998 (or a single Firefox tab in 2013). I wanted to get rid of this old Apple junk so I could buy newer, more expensive Apple junk. But to do that, I had to ensure the disks were securely wiped.

Say goodbye to the iMac.

Thankfully the popular Darik's Boot and Nuke (or DBAN) tool is available for the PowerPC (PPC) platform, which you can grab from SourceForge. The latest version of DBAN for PPC is 2.0.0. I can't imagine many people perform secure wipes of pre-Intel Macs these days, but apparently I'm one of 11 people this week who have downloaded DBAN for PPC!


I'm guessing it's me and 10 web crawlers.

DBAN gives you a few options for wiping a disk, depending on how paranoid you are. You can pick the source of entropy, the Pseudo Random Number Generator (PRNG), how many passes, and whether to verify the passes. A lot of options for formatting a disk: had I designed the DBAN interface, I'd have just specified paranoid, ultra paranoid, Fox Mulder, Security Architet, Fox News Anchor.

I chose a DoD 5220.22-M (aka "DoD short") wipe which is fancy terminology for overwriting the contents of the disk with random information three times, and verifying that the write completed successfully. I used the default Mersenne Twister PRNG, which is a fancy system for ensuring that the random numbers are indeed random, and not just the number nine.

A random Dilbert comic.
I thought the wipe was going fast: 40 minutes in and 40% done, then I realised the disk size was only 6 GB! We have it good these days. Now let's watch a blue screen which isn't Windows crashing due to me overclocking the video hardware!

The data will become irrecoverable...BECAUSE THE DISK WILL
HAVE DIED BEFORE THE WIPE IS COMPLETE.



And good things come to those who wait. According to the hardware clock powered by a dead battery, the year is now 1956 and I have spent negative 56 years waiting for the wipe to complete. Forget saying hello to the iMac: say hello to the UNIVAC.

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