Comment by drostie | Hacker News Reader

Comment by drostie | Hacker News Reader

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I had a nightmarish scenario a few months back where I was just trying to wipe an old hard disk on an old laptop that still barely worked, so that I could ship it off to an electronics recycling place. It was I think 512MB of RAM but might have been less; but a few popular Linux LiveCDs wouldn't boot without running out of RAM, and my `prng` script uses Python3 among other things. After trying desperately to set up swap on a thumbdrive before the computer ran out of memory, I eventually just caved in and went to a comp shop to find an external hard drive case for old laptop drives. I was lucky, found one for relatively cheap, and wiped it from my own computer. And doing that sort of command from your own computer is quite terrifying even if you think you've taken the proper precautions, you're still double-checking everything to make sure that /dev/sdb is really where the random bits and then zeroes should go.

So these articles are appearing a little after I'd have liked to see them but they're a welcome overview in any case. :D

This has been one of the most helpful PC troubleshooting tool purchases I've ever made:

2.5"/3.5"/5.25" SATA/IDE to USB 2.0 Adapter ($17.99) http://www.newegg.com/Product/Product.aspx?Item=N82E16812232...

Also, I usually pull out the hard drive I'm worried about accidentally wiping and boot from a live CD.

Or you could have just booted to a console with no WM at all and wiped it?

He could also have used /dev/urandom to generate his random bits instead of running a python script.

Or /dev/zero, much faster.

I wanted to get some data off an old Windows 98 laptop of 1999 vintage. 4Gb hardrive, 1 usb port, 64 Mb of RAM. It worked fine in Windows 98, but back then anything USB required extra drivers and ... well, let's just say I didn't think re-learning Windows 98 at this stage in my life was a worthwhile investment.

In the end, I used Damn Small Linux live-booted off a CD and copied the whole drive to a USB stick. Took hours due to only having USB 1 back then, but it worked. Your external drive case is a better solution, but the "old distro" approach is great for cheapskates :-)

Why didn't you just take the hard drive out and take a hammer or power drill to it?

This might have been more fun but there exists the possibility that someone might ransack the laptop for components, and I actually like the idea that they might be successful.

You only need to overwrite a single time with 0s to make sure noone can recover the drive. (But using the drive's secure erase ata command is better.)

Or you could have used DBAN, which has modest min spec requirements.

I thought that too but late last year one of these Bradley Manning articles seemed to suggest that data might be able to persist after a simple zero-fill, so I thought I'd use my prng script before zero-filling, because it's as fast as zero-filling and it seems unlikely you could decipher more than two layers.

I looked up the article; the statement is actually more ambiguous than I recall:

http://www.wired.com/threatlevel/2011/12/manning-assange-lap...

"Johnson testified that he found two attempts to delete data on Manning’s laptop. Sometime in January 2010, the computer’s OS was re-installed, deleting information prior to that time. Then, on or around Jan. 31, someone attempted to erase the drive by doing what’s called a “zerofill” — a process of overwriting data with zeroes. Whoever initiated the process chose an option for overwriting the data 35 times — a high-security option that results in thorough deletion — but that operation was canceled. Later, the operation was initiated again, but the person chose the option to overwrite the information only once — a much less secure and less thorough option. All the data that Johnson was able to retrieve from un-allocated space came after that overwrite, he said."

It's not clear what "after" means exactly, but it surprised me that he learned about the first attempt after the second attempt was complete. What may have happened -- making this much less impressive -- is that maybe /dev/sda1 was filled with /dev/zero rather than /dev/sda, so that the first part of the drive was totally untouched. So it might be much less impressive than it sounds, but it sounded impressive to me at the time.

For this reason I have a drawer full of hard drives, its just so much easier.

Why would you have a drawer full of harddrives when, with the aid of a screwdriver, you can have a fridge door covered in magnets!

This is because you don't know what's out there.

Damn Small Linux runs in 16MB of RAM and provides a GUI by default:

http://www.damnsmalllinux.org/

tomsrtbt runs in less, but provides no GUI and very little documentation:

http://www.toms.net/rb/

http://www.linuxtoday.com/news/1998122400805PR

My point is that not everything needs to be small. We have freedom of choice here, not one-size-fits-all, and we can create specialized distros for specialized tasks.

Right, it's more that those were the LiveCDs which I had on hand to try and I didn't want to research alternatives. What I really should have done at the time is to ask around on Freenode or some other IRC network; someone could probably have answered the question quickly.

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