This article is telling everyone that if you really want your data to be safe when you throw away your computer, you need to beat the thing to a pulp with a hammer.
The most straightforward solution, according to Which?, is complete destruction - and it recommends using a hammer.Frankly, I think that this article is irresponsible. In a nutshell, the article is saying that yes, you can find software out there that will erase your data securely, but the only way to be completely positive is if you beat your hard drive with a hammer. This, I believe, does a disservice to the non-computer experts of the world. Consider a case of two identical hard drives, one beaten to pieces and the other overwritten a single time with random data. Which one would be easier to retrieve data from?
If you're that worried, get rid of it properly: burn it or put it in acid.
The answer is the broken one. Now I wouldn't want to be the guy to have to do it, but you can piece together all those broken platters and recover data from them. I was watching Forensic Files a few months ago and they had a case where someone had cut up a 5 1/4 inch floppy drive with scissors and the Department of Defense was able to piece it back together and get the data. On the other hand, recovering data that has been overwritten with other data is as close to impossible as I would say you can get...and it becomes less possible as hard drive densities increase.
Once upon a time there was a man named Peter Gutmann who suggested that with the use of an electron microscope you might be able to figure out what was once written to a part of a hard drive that had been overwritten. That lead people to come up with policies like "you have to overwrite 7 times before it is safe to dispose of." However, despite all the assurances I've heard that it can be done, nobody knows anyone that has actually done it. A couple years back I took a forensic class with Mike Murr from the SANS institute and he was talking about this very thing. Everyone knows someone that has done it, but nobody has done it themself.
I should be clear that I'm talking about data that has been deleted and overwritten by the operating system or some other software. Here is a great quote from the Wikipedia entry on the subject:
Daniel Feenberg, an economist at the private National Bureau of Economic Research, claims that the chances of overwritten data being recovered from a modern hard drive amount to "urban legend". Daniel Feensberg also points to the interesting fact, that the "18 minute gap" Rosemary Woods created on the tape of Nixon discussing the Watergate break-in, has not been recovered. An easy task compared to recovery of a modern high density digital signal.I'm worried about people like my dad. He's going to read something like this and instead of looking for some free software to clear his old hard drive, he's going to take it out to the garage and hit it with a hammer. He's going to go through all that work and possibly give himself a heart attack when he could have sat in his living room chair, watching TV and actually had better protection. Poor dad. Please don't let this happen to your dad. Spread the word that overwriting or encrypting your data is more effective than pulverizing it.