[cargo0d]

I have a 1.25 eMac with an 80 gig hard disk running Panther 10.3.5. I want to securely wipe data from it so I used "8 Way Random Write Format" in disk utility. It wrote random data to the hard drive for about 48 hours, until it showed half finished in the progress bar. Then about 24 hours ago the window changed its venue from writing random data to "Creating Partition Map". The progress bar has ceased to move from the halfway point and the the rainbow wheel cursor is still spinning. Is this normal or has disk utility "froze"? If this is typical behavior, then how long does it take to finish the process of wiping the hard drive? Thank you in advance for any assistance.

[Goldfinger]

It sounds like it's frozen but I couldn't say for sure. Keep in mind that those 8 way random write formats can take a loooooong time. So I would let it sit for another 24h.

[FireWire]

A few days to erase a hard drive?! Do you guys work for the CIA or something?

[Goldfinger]

Yeah it's probably more time efficient to format the disc write it full of random crap format it again etc.

I don't really get why you would do an 8x format anyway. Unless you're really paranoid or have top secret documents on that machine.

[Millennium]

8-way random writes do take a long time: after all, the drive has to be completely overwritten bit-by-bit eight times. The bit about freezing in the middle, however, definitely isn't normal.

Unfortunately, the only thing I can think of to do is to force-quit Disk Utility and try again. The data on the drive is going to be lost -you'll have to format it again- but since you were trying to format it anyway I take it this won't be a problem. This time, I would suggest a less time-consuming formatting method. Since you probably got through four or so runs of the 8-way random write, the benefits will still mostly be there.

By the way, no software can ever truly destroy the data on a hard drive. You can get it to the point where no one short of an intelligence agency can get at the data, but they have methods involving scanning tunneling microscopes which can get the data even through random writes. If you want to truly destroy data beyond recovery, what you need is a sledgehammer. It's a lot faster than an 8-way random write, and it's a lot more fun. Smash the platters to pieces, and then dispose of them in at least two separate locations. Technically an intelligence agency could even recover data this far gone, but they're going to have to really want to get the data from the drive, because recovering the pieces is going to be a long, expensive, and thoroughly miserable process.

To go truly beyond any hope of recovery, don't stop at smashing the drive. Melt them into a chunk of metal (intelligence agencies use thermite for this purpose), then smash the chunk again. The high heat of the melting process will well and truly demagnetize the material. Then dispose of the pieces in separate locations, as before.

Personally, though, this last bit is pretty excessive. Just smashing the hard drive is reasonably fast, damn secure, and most important of all, fun.

[FireWire]

I don't know about the technologies used to recover information, especially the microscope you mentionned, but I was wondering: since the drive is written over 8 times with random data, how do agencies know which part is yours? Do they count the iteration? It's not like each data "generation" is sedimented on top of the precedent, like rocks A given bit may have held the values {2,3,6,0,3,7,1,9} during the process, and the next one too... it may be a bit tedious to mix'n'match them to find something coherent!

Beside, your comment about the sledgehammer reminded me about a question I had recently after my friend told me a story that happend to him a few weeks ago. The police, through IP confusion, thought he was a big hacker and ended up searching his whole appartement, including his computer, which, fortunately, contained nothing questionnable. But what if... Is there any solution that quicky destroys a whole hard drive, while keeping it safe the rest of the time?

[foil-hat mode]
I was thinking about an external FireWire drive, using a FileVault-like 512-bit on-the-fly encryption, which would be equipped with a physical mechanism that would render the drive unrecoverable after activating a few security measures to be sure it is not invoked accidentally. It could be a strong magnet or even a quick "burst" that would be contained in a metal encasing...
[/foil-hat mode]

[CharlesS]

Millennium's probably right - if it got to creating the partition map, it probably has already finished writing the random data 8 times. Therefore, your data should be thoroughly hosed already, and you should now be able to do a plain old reformat.

[osxrules]

Here's some info about disk drive recovery:

http://www.wired.com/wired/archive/3.10/data_pr.html

It seems you're safe with 10 overwrites. But yeah, you'd be quicker just breaking it. Hard drives are pretty cheap anyway.

What I'd like to see in the future is where computer hard drives are removable just like small flash cards or whatever. That probably won't be for decades yet but we already have 60GB+ flash hard drives.

[Millennium]

There are hard-drive enclosures in existence which will strong-encrypt the data on them automatically. Because it's done in hardware, it's both very fast and completely transparent: the computer never knows it's writing to an ecrypted disk. I've yet to use one of these, but I assume that the encryption keys are stored on some kind of removable dongle, which you could pull out and destroy if you absolutely had to.

[Morpheus]

Originally Posted by Millennium

8-way random writes do take a long time: after all, the drive has to be completely overwritten bit-by-bit eight times.

Yeah, but the option "zero all data" only took a few minutes when I did it once whereas 8-way random took 10 about hours. So there has to be something more going on. Generating random bits isn't that hard.

[steve626]

I recently "zeroed all data" (1-way, not 8-way) on two Seagate 300-Gig external firewire drives with a 1.33 GHz Powerbook. In each case, it took exactly the same amount of time, about 6 hrs. So I would expect about 1.5 hrs for doing this on a 80-Gig drive, and for 8-way I'd assume 8-times as long which would be about 12 hrs for the 80-Gig drive. Sounds like something went wrong with the original poster's attempt, suggest that he try again and leave the computer with nothing else going on while the format is occurring.

I am amused by the postings here where people worry about the degree to which someone might go to get at "their stuff." There are probably much easier ways to get at your bank balance than taking your drive to drive savers and paying thousands upon thousands of dollars to get some scraps of bits off the disk (and why would anyone care). I have personally never heard of any normal person's disk being scavaged like this after a 1-way write of zeros, let alone more than 1-way. I think it would be easier to just break into someone's house and break the locks on their file cabinets to get to financial information, or just bribe someone who works for a bank or credit card company ... that's what would worry me more. Meanwhile you guys can continue to enjoy yourselves melting your drive, smashing them with mallets, etc.

[Macpilot]

I would try the zero erase (one pass) method and see if that works. If that does not work than you have a problem with that HDD.