Skeletons on your hard drive

CNet.News.com ^ | 4/20/2005 | Matt Hines

[Mike Bates]

Tax records, resumes, photo albums--the modern hard drive can keep increasingly larger volumes of information at the ready. But that can turn into a problem when it comes to effectively erasing the devices.

There are a number of options for cleansing the drives of unwanted computers, from special wiping software to destruction services to manufacturers' recycling programs. But what many PC owners don't realize, experts say, is that these methods are often not enough.

[SAJ]

Very useful site, thanks!

You will admit that it's a bit odd, though, to label the interrupt as ''diskette services'' when in fact it can service any drive. This almost has to be a modification implemented after Win 95; little if any need for the diskette services to double-up for hard drives in the days of MS-DOS.

[Leatherneck_MT]

There are a number of options for cleansing the drives of unwanted computers, from special wiping software to destruction services to manufacturers' recycling programs. But what many PC owners don't realize, experts say, is that these methods are often not enough.

There is only one way to securely remove data from a hard drive disk.

Turn it into Ash.

[whd23]

You will admit that it's a bit odd, though, to label the interrupt as ''diskette services'' when in fact it can service any drive.

Oh yeah, BIOS is very odd. In 2001 I spent some "quality time" with the Phoenix BIOS source code, modifying it for our custom Pentium-III Compact PCI processor card. Let's just say I've had better times at work! I ended up printing out a lot of that site that I referred you to.

P.S. I posted the link as an informational link for you, not as an intented correction.

[SAJ]

Not a problem, thanks again for the info.

Out of curiosity, I've just dug up Ray Duncan's old classic, ''Advanced MS-DOS'', 1990 expanded edition -- not one single word in it about using INT 13h for hard-drive access. Wonder when it was changed?

[DelphiUser]

I enjoy taking old hard drives apart, running a magnet over them and then making a mobile out of the case.

Cool looking parts in there! After hanging in the wind and rain for a while, good luck getting anything off of it ever :-)

[LurkedLongEnough]

Sounds labor intensive--unless you would consider a belt or orbital sander, or maybe a sand blaster?

:-0 LOL

There is another alternative. I would give the drive to Hitlery and ask it to memorize the contents. Of course, later it wouldn't be able to recall a single thing!

[MD_Willington_1976]

You'd need a very strong magnet. A fridge magnet or speaker coil magnet would not work.

MD

[Outlaw76]

Haven't had to do it recently, but if I remember correctly a good low level format (done by BIOS) changes every bit to zero effectively cleaning the drive. Some information may still be stored in hidden sectors, but it won't be your every day skeletons. The last time I did that it took all night on an old 512mb HD.</p>

[IamConservative]

You might be a Red State voter if...

- you use your scrap computer gear for target practice.

- take your drop lawn spreader, high nitrogen fertilizer and spell RAT in your liberal neighbors front dandelion patch.

(I, ugh, heard that second one from a friend. Any resemblance to actual occurrence is coincidence I'm sure.)

[raccoonradio]

>>What did you say your SS number is?

ha--There's another bit of privacy that people give away far too often! I changed my driver's license so I have a separate number instead of my SS number. (And by the way folks, when you get emails from Ebay or PayPal (supposedly) saying you need to verify some info --don't fall for it! They're
scamming people that way too--spoofing email addresses as part of it)

[The Red Zone]

How about microwaving the platters.

[onyx]

LOL-LOL-LOL...
now I continue reading the other comments hoping to find a solution.

[Flying Circus]

Where I work, I have and even more sure way of distroying the data on a hard drive: large degaussing magnets. I think the drive could even be used again afterwards too.

[onyx]

After plodding thur the article in its entirety and all of the comments, your solution still stands as the most effective... lol.

[Flying Circus]

A simple magnet won't work to erase data if someone has tools to get it. What is needed is a very strong electromagnet running a degaussing routine... degaussing involves a frequent 180 degree field reversal with a declining strength. The key is to randomize all the bits many time over. A unidirectional magnet will put the bits in one direction, but by reading the relative strength of the bits, the data can be reconstructed with ease.

[nickcarraway]

Doesn't being constantly awakened all through the night have thhe same effect on the human mind?

[Flying Circus]

Writing all the data in one direction doesn't work. The relative strength of the bit field can still tell you what the ones and zeros were.

[Flying Circus]

I'll have to ask my wife. hehehe

[MD_Willington_1976]

Magnetic susceptibility of hard-drives is low to increase reliability & data integrity.

Magnetic susceptibility is the degree of magnetization of a material in response to a magnetic field.

You need a device capable of high coercivity to overcome magnetic susceptibility.

Coercivity is the intensity of the magnetic field needed to reduce the magnetization of a ferromagnetic material to zero after it has reached saturation.

You could take a motor coil and place the hard-drive inside of it and then apply a large current to the field windings, that would more than likely erase the contents of the drive. This offers a high coercivity since an intense magnetic field is created that can overcome the susceptibility.

I deal with this in a similar area, power transformers and power transformer protection.

MD

[MD_Willington_1976]

Yep...see my other post.