Ways to *REALLY* erase a hard drive?

[John Woodgate]

I read in sci.electronics.design that Barry Lennox
[email protected]>) about 'Ways to *REALLY* erase a hard drive?', on Sat, 12
Feb 2005:

I used to use one that look a little like a microwave oven, and the
manufacturers blurb stated it used a charged cap dumped through a coil.
Never saw a schematic or got to look at it's guts however.

I made a magnetizer for model railway motor magnets that way about 50
years ago. Rectifier straight off the 240 V mains to a 20 uF cap through
10 kohms. Switch to connect the cap to a 'no-volt coil' from a motor
starter - lots of turns. Custom-made magnetic circuit (the railway nerd
provided that from his machine-shop).

Interesting that the switch current is initially zero and finally zero,
so no arcing problems, but in between, about 2 A.

 

[Scott Miller]

Super magnets (AIUI) will not do a bulk erase od the disk.

Thermite works for me.

Damn, stole my favorite technique. Getting the thermite lit is the tough
part - magnesium helps for that. I figure what you really need is a ceramic
holder for the drive that'll keep the molten stuff in one place and turn the
whole thing into a lump of slag, rather than melting straight through.

You may want to remove the drive from the PC first, too.

Scott

 

[TCS]

I recently had a 80 gig Maxtor hard drive die on me. Though it was still
under warranty (just) I decided a much better use for it was to turn it into
a show-and-tell for the local elementary school kids. I finally managed to
get the cover off the thing, exposing the inner platters. Someone told me a
Torx 10 would fit those crazy screws on the cover plate - they were wrong.
I had to drill them off. Now, I need to know a sure fire way of wiping data
off the platters for good. The machine died before I could erase it inside
the computer, so far I have a bunch of 'super magnets' which I dropped
directly onto the platters and let them stay there overnight. Do you think
this is enough? I would like to get them as deleted as I can possibly get
them, but still be able to use the drive as a demonstration device for the
kids. Thanks.

Remove the cover. Remove the platters and sand off the media. (DoD trick)

 

[Dave VanHorn]

Widlarize it.

 

[Reg Edwards]

Try a hammer and chisel. It works for me.

 

[Rich Grise]

Hello,



The platters on some newer hard disks are made of glass. I believe the
later IBM DeskStar* (tm) series were among the first to have glass
platters. I'm not sure what the advantage is to glass, but I'd certainly
like to take one apart and have a look!

It's light, and you can get an optically smooth surface easier (read:
cheaper) than on aluminum.

But really. Once you've opened the drive it's done, unless you get it
confiscated by some kind of black ops people.

Like that other person asked, what is on this drive? And I'd add, if it's
that sensitive, what are you doing carting it around as a demo?

Thanks,
Rich

 

[Rich Grise]

Damn, stole my favorite technique. Getting the thermite lit is the tough
part - magnesium helps for that. I figure what you really need is a ceramic
holder for the drive that'll keep the molten stuff in one place and turn the
whole thing into a lump of slag, rather than melting straight through.

You may want to remove the drive from the PC first, too.

At the shop where I sit, they have a plasma cutter. Much less messy than
thermite. ;-)

Cheers!
Rich

 

[me]

Damn, stole my favorite technique. Getting the thermite lit is the

just put it all in a hole in the ground...

 

[keith]

Well, then bending would take care of the data recovery problem.

So would folding, spindling, or mutilating.

 

[TCS]

Widlarize it.

and WTF is it to widlarize something?

 

[Michael A. Terrell]

and WTF is it to widlarize something?

Are you a newbie or something? Do a web search for Bob Widlar.

 

[Rich Grise]

Are you a newbie or something? Do a web search for Bob Widlar.

What does designing the 741 and dying at the tender age of 53 have to do
with erasing data off a drive platter?

BTW, google search on "widlarize" returns null.

Thanks,
Rich

 

[xray]

BTW, google search on "widlarize" returns null.

Google doesn't always work. One story defining the term is in the middle
of this article...
http://www.national.com/rap/Story/widlar.html

 

[Barry Lennox]

What does designing the 741 and dying at the tender age of 53 have to do
with erasing data off a drive platter?

BTW, google search on "widlarize" returns null.

You are correct, nothing! That's surprising.

Nevertheless to "Widlarize" something, is to take a hammer and beat
the thing into little bits. Bob Pease has often written about it.

Barry Lennox.

 

[Guy Macon]

BTW, google search on "widlarize" returns null.

That's because you didn't click on the "groups" link.
It takes you right to a post defining the term.

 

[Tom Del Rosso]

2ea 520MB western digital drives. Standard office environment,
drive cover removed, running DOS scandisk in a looping bat file.

First drive lasted 8 hours. Second drive lasted 4 hours.

I expect that even a simple dust cover would extend this time,
and that a newer, higher capacity drive would crash sooner.

Are those the times before the first sector error?

 

[Guy Macon]

Are those the times before the first sector error?

Those were the times before DOS scandisk running in a looping
bat file stopped with an error.

I am surprised that I haven't seen a bunch of posts from folks who
have tried this. Doesn't everybody has an old 100MB drive or two
laying about?

Guy Macon <http://www.guymacon.com/>






Guy Macon <http://www.guymacon.com/>

 

[Tom Del Rosso]

Those were the times before DOS scandisk running in a looping
bat file stopped with an error.

I'm thinking maybe most of the other sectors were still readable.

I am surprised that I haven't seen a bunch of posts from folks who
have tried this. Doesn't everybody has an old 100MB drive or two
laying about?

Yeah, but I'm not sure of their reliability with the cover on, so it would
be hard to compare. A new drive might last longer. OTOH, a new drive might
be more sensitive. I don't know if I could do a meaningful test.

 

[Guy Macon]

I'm thinking maybe most of the other sectors were still readable.

It depends. If the platter was damaged, yes. If the head was
filled with oxide, it might be all bad reads. If I ever do it again
I will test for that.

 

[Ben Bradley]

I recently had a 80 gig Maxtor hard drive die on me. Though it was still
under warranty (just) I decided a much better use for it was to turn it into
a show-and-tell for the local elementary school kids.

I'd get a warranty replacement drive, and then get a cheap computer
at a thrift store to open up. But that's me.

I finally managed to
get the cover off the thing, exposing the inner platters. Someone told me a
Torx 10 would fit those crazy screws on the cover plate - they were wrong.
I had to drill them off.

Torx, schmorx. The first step in doing "physical experiments" on a
hard disk drive is using a Dremel (brand of handheld hobby motorized
tool) with a cutoff wheel to cut head slots in the screws for a
regular flat-blade screwdriver which then easily removes the screws.
It's easy, works great, and it's not like you're going to have to put
it together so that no one knows it's been taken apart.