Wiping a dead hard drive

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Al your talking apples and oranges.... once that mag CONTACTS the surface of
the HD, it will be clean and a great magnet itself for awhile. Done deal
many times, just to screw around during my younger days.

No MRI experience and a tech would be a little harder to convince to use a
piece of equipment such as that, than a burley beer guzzling equipment
operator, and if I guess, like yourself, I would guess that a MRI will have
a dramatic effect on the HD.

Al Dykes said:
power / size well lets see...a visit to the local wrecking/metal recycling
yard would do the trick.
Click to expand...


And what makes you thing that ? Don't mistake the strength of the
magnetic field with the lifting ability of a magnet with a large
surface area, but moderate field intensity.

I think a medical MRI is the strongest magnet you'll find outside
an advanced physics lab.
Click to expand...
 
Al your talking apples and oranges.... once that mag CONTACTS the surface of
the HD, it will be clean and a great magnet itself for awhile. Done deal
many times, just to screw around during my younger days.
Click to expand...

But you didn't demagnetiize a modern hard disk.

The magnetic materials used to coat the platters of a modern hard disk
have an amazingly high figure of Coercivity. A disk head flys a few
millionths of an inch over the surface and generates a magnetic field
that is very powerfull, but only a few milionths of a square cm in
cross section.

Coercive force, Hc The demagnetizing force, measured in Oersteds
necessary to reduce the induction, B to zero after a magnet has
been previously saturated.

http://www.rare-earth-magnets.com/magnet_university/glossary.htm

If a magnetic field that string was, say, a square inche in cross
section it would yank you belt buckle off (if it was magnetic). MRI
machines can do things like that.





No MRI experience and a tech would be a little harder to convince to use a
piece of equipment such as that, than a burley beer guzzling equipment
operator, and if I guess, like yourself, I would guess that a MRI will have
a dramatic effect on the HD.
Click to expand...
 
You might want to consider that the strength of the magnet is not the only
factor. MRI coils are big because you have to be able to put a person inside
of it. A much smaller magnet could exert more power into a smaller object
using less power. Distance does have an affect.

I put 3.5" floppies into an industrial demagnitizer, it lookded like a mini
MRI coil, we used to demagnitize machined bar stock. It would make a
screwdriver vibrate and become warm if left in it. It would not erase the
floppies or even cause errors. So it wasn't putting as much force on the
media as the little head in the drive.

Frequency might be another factor.
 
You might want to consider that the strength of the magnet is not the only
factor. MRI coils are big because you have to be able to put a person inside
of it. A much smaller magnet could exert more power into a smaller object
using less power. Distance does have an affect.

I put 3.5" floppies into an industrial demagnitizer, it lookded like a mini
MRI coil, we used to demagnitize machined bar stock. It would make a
screwdriver vibrate and become warm if left in it. It would not erase the
floppies or even cause errors. So it wasn't putting as much force on the
media as the little head in the drive.

Frequency might be another factor.
Click to expand...


http://www.diagnosticimaging.com/dinews/2004041302.shtml

"A system to detect objects that can turn into projectiles in
the magnetic field of an MR scanner could prevent accidents
causing personal injury and equipment damage. A specialized
metal detector being marketed by ETS-Lindgren that can be
mounted in the doorway leading to an MR suite allows staff and
patients to be scanned automatically. An alarm sounds when the
device detects ferromagnetic metal, but not MR-compatible
objects, such as an aluminum oxygen tank."

I can't think of any other industrial magnet, outside of governemt
research labs that has this kind of safety issue.

Frequency is an issue only to the point that inductive heating lowers
the curie point in the magnetic material.
 
I'm not going to get into the physics of the subject(alt.science).
Modern HD, what arbitrary year would you put on the beginning of the
'modern' HD? 1985 - 1995 - 2005

Al Dykes said:
Al your talking apples and oranges.... once that mag CONTACTS the surface of
the HD, it will be clean and a great magnet itself for awhile. Done deal
many times, just to screw around during my younger days.
Click to expand...

But you didn't demagnetiize a modern hard disk.

The magnetic materials used to coat the platters of a modern hard disk
have an amazingly high figure of Coercivity. A disk head flys a few
millionths of an inch over the surface and generates a magnetic field
that is very powerfull, but only a few milionths of a square cm in
cross section.

Coercive force, Hc The demagnetizing force, measured in Oersteds
necessary to reduce the induction, B to zero after a magnet has
been previously saturated.

http://www.rare-earth-magnets.com/magnet_university/glossary.htm

If a magnetic field that string was, say, a square inche in cross
section it would yank you belt buckle off (if it was magnetic). MRI
machines can do things like that.
Click to expand...
 
I'm not going to get into the physics of the subject(alt.science).
Modern HD, what arbitrary year would you put on the beginning of the
'modern' HD? 1985 - 1995 - 2005
Click to expand...

I think cheap hard disk densities took off around 2000. IBM did lots
of the physics that makes these disks possible, and a google
search finds an IBM reasearch paper dated 1995. 5 years to market
is about right.

http://domino.research.ibm.com/tchjr
/journalindex.nsf/0/312fbbd32e8930bd85256bfa0067fb03?OpenDocument

http://makeashorterlink.com/?M23C142C9
 
Take a sledge hammer and apply a hammering action to the platter.
This will make retrieval extremely difficult. Believe it or not, we
used this procedure for drives, monitors and printers to protect
classified government data. What the price of your sensitive data
getting into the wrong hands?
 
Hi, all

Anyone know a practical, effective way to erase a hard drive that is deader
than a brick?

It's a West. Digital 60 gig 7200 RPM. It won't spin up and
WD's diagnostic utilities won't recognize it. It went out a few days before
the warranty expired and I want to try to return it, but it has _lots_ of
sensitive info on it, and, dead or not, I don't want it in the hands of
strangers.

By practical, I mean something not too hard to get access to. Running it
thru an MRI scanner might be worth a try, but not too practical....

Thanks!

Mike
Click to expand...

Mike, If destruction is your choice save the hard drive case. It
makes a perfect fan housing. I cut a hole in the case and mounted a
fan into the case to make a cooler. The metal can be easily cut or
drilled for fan mounting holes. It is now mounted just above my new
drive and keeping it cool.
 
that's your contribution?,...

so a ball peen hammer would be better. seems to me if you turn in a
bent -spindled or otherwise mutilated HD, there could be a question on
the warranty validation... But wait with the magnet.. the data would
be actually on the surface of the magnet...what if somebody took the
150 years to retrieve the bits and then reassembled them to find his
pictures of the backyard. practical would be to 'send the damn HD
back' and get on with it.
 
Forget it.

Buy a new one on sale, send in the rebate, and hit the old one with a
sledgehammer once or twice.

Usually there's a good, cheap, sledgehammer at the local flea market.

Don't forget your safety glasses ;)
 
Actually, you would be better off with a 44-40 or .357mag or a similar
style of bullet. All the 30-06 cartridges I've seen have a jacketed
bullet which would probably put a 30 calibre hole in the center of the
disk, assuming that you are a fair shooter. The 44-40 or .357mag or
the like would have a blunt nose and maybe be a hollow point and at
the most semi-jacketed. This would cause the projectile to impact with
a larger size because of deformation and there fore tear the hell out
of the disk no matter where the bullet impacted. But YMMV.
 
Rich said:
Jeez -- why all of these violent solutions? Physical destruction is,
indeed, the only reliable way to ensure that the data is not recoverable
but that can also be accomplished by just taking the thing apart.
Salvage what's re-useable and use the rest for geek Xmas-tree ornaments.
Click to expand...

Did you ever try to take apart a drive? They mostly use those hexagonal
screws (the name of which escapes me). The last time I had to drill 'em
out.

I must admit that the magnets inside are worth saving :-)
 
torx

Paul said:
ornaments.

Did you ever try to take apart a drive? They mostly use those hexagonal
screws (the name of which escapes me). The last time I had to drill 'em
out.

I must admit that the magnets inside are worth saving :-)
Click to expand...
 
Did you try it ? Could you format and reuse the disk, afterwords ?

What vintage disk ? It makes difference.
Click to expand...

I have tried this, and it did work in that all data (or readable by
me, anyway) was gone, but I did not try to reformat the disk as I was
more concerned about TOTALLY nuking my tax returns off a 1 gig drive I
did not intend to use again.

I sold the drive and the surrounding Pentium I AT machine at a yard
sale for $10 as I recall.

R.
 
First, thanks to all who replied, especially to those who read the whole
post and noticed that I was after warranty replacement, and thus was seeking
an alternative to physical destruction.

I thought a heavy duty degausser might do it, but don't have access to one -
and was hoping somebody would make a suggestion that triggered an idea or
memory of a contact who could put me next to one.

Then several suggested that no magnetic field outside of (maybe) an mri
scanner would do it- but others said they had done it successfully with a
degausser soooo..... my nearest friend in a radio station is 450 miles
away - too far to be practical right now.

A couple reasons I wanted it replaced: a new drive of same size costs 55 to
70 bucks, which I didn't want to spend. A super shopper said they cost 40,
but I couldn't find any at that price - which, after all, would be 34 plus
shipping. And, the damned thing failed. All that data was on there because
I,personally, have never had a drive fail before the warranty expired. I
know they do, I have replaced other people's drives that failed after 6 or
seven months, but, personally, no. I have drives that are still running
after 10 years. So I wanted the company to bear part of the burden of a
defective product.

The person who said, just send it back, they won't bother trying to revive
it, is probably right, but since it contains tons of financial information,
paswords, and other forms of ID, I didn't feel comfortable with that
probably. I think a chip or other element on the circuit board failed. So
if the thing fell into the hands of the wrong person, it would be simple to
revive. Again, that's not probable, but as we all know, there are people
out there who steal in every conceivable manner, so being paranoid seemed
the logical thing to do. Sraightening out financial/identity theft can take
years.

So far, I've tried wiggling, jolting, tapping with screw driver, rapping the
sides of the drive against a table and freezing. All I need is for it to
run long enough to wipe, even in an "insecure" manner. I am willing, even
in my paranoid state, to conceed that the thieves this drive might encounter
are probably not going to use data recovery software, and definitely not use
an electron scanning microscope. But none of the above methods worked.

Next comes heating and slamming hard on to a concrete floor. I doubt I can
keep the drive square enough with the floor to avoid evidence of abuse, so
that's the last step before the hammer.

BTW, somone, "kenny" I think, provided a good link to many tales of drive
revival, here: http://techrepublic.com.com/5100-6255-5029761-2.html .

Mike
 
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