| Author |
Message |
Nick Chalk
Guest
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 Posted:
Mon Nov 21, 2005 9:26 pm Post subject:
Coercivity of current HD platters? |
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Does anyone have an idea of, or references for,
the coercivity of current HD platters?
I'm looking at degaussers for a charity
refurbishing/recyling project, and I've found a
wide variation in the specs of devices claimed to
be able to wipe hard disks. Before we spend UKP 1k
to 2k, I'd like to be sure that the machine will
do the job.
We already use software wiping tools, but need a
device to handle faulty drives. Given the nature
of the project, and the volume of drives, I don't
think physical destruction is feasible.
Thanks for your help.
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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robertwessel2@yahoo.com
Guest
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| Posted:
Tue Nov 22, 2005 9:15 am Post subject:
Re: Coercivity of current HD platters? |
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Nick Chalk wrote:
| Quote: | Does anyone have an idea of, or references for,
the coercivity of current HD platters?
I'm looking at degaussers for a charity
refurbishing/recyling project, and I've found a
wide variation in the specs of devices claimed to
be able to wipe hard disks. Before we spend UKP 1k
to 2k, I'd like to be sure that the machine will
do the job.
We already use software wiping tools, but need a
device to handle faulty drives. Given the nature
of the project, and the volume of drives, I don't
think physical destruction is feasible.
|
If you actually degauss a semi-modern hard disk, it will no longer be
usable in any fashion. In short, you will not be able to reformat it,
at least not without proprietary information from the vendor (which
will likely be different for each model of disk drive). And that's the
best case - some drives will require additional external hardware to
low-level format.
So if you're recycling these drives, degaussing is *not* the answer.
On the flip side, if you're destroying the drives, I don't think
*anyone* serious about security will accept degaussing an assembled
drive as secure. Running a HD through a degausser may cause enough
damage to make the drive unusable, but not enough to prevent someone
serious (like the high end data recovery folks) from recovering
significant amounts of data. Some of those folks might accept
degaussing individual platters.
The usual high end solution is to disassemble the drive, and physically
destroy the individual platters and circuit board. Your local foundry
has a furnace that will make short work of both. ;-) |
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Nick Chalk
Guest
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| Posted:
Tue Nov 22, 2005 10:17 pm Post subject:
Re: Coercivity of current HD platters? |
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robertwessel2@yahoo.com <robertwessel2@yahoo.com>
wrote:
| Quote: | Nick Chalk wrote:
Does anyone have an idea of, or references for,
the coercivity of current HD platters?
If you actually degauss a semi-modern hard disk,
it will no longer be usable in any fashion.
|
I know. We're looking for a method of wiping
faulty drives.
| Quote: | So if you're recycling these drives, degaussing
is *not* the answer.
|
We want to recycle, not refurbish, them.
| Quote: | On the flip side, if you're destroying the
drives, I don't think *anyone* serious about
security will accept degaussing an assembled
drive as secure.
|
Has anyone studied this? I've read this opinion in
several places on the Net, but not yet found any
evidence, for or against.
What is the coercivity of a hard disk platter? How
much does the case attenuate the field? Does a
modern write head achieve saturation of the
magnetic material? Those are the questions I'm
looking to answer.
| Quote: | The usual high end solution is to disassemble
the drive, and physically destroy the individual
platters and circuit board. Your local foundry
has a furnace that will make short work of both.
|
I don't think we have a local foundry - it's all
light industry around here, now.
The closest forges I can think of are South Wales
and Sheffield. This is the UK - a hundred miles is
a long way.
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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Paul Rubin
Guest
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| Posted:
Thu Nov 24, 2005 1:16 am Post subject:
Re: Coercivity of current HD platters? |
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Nick Chalk <nick@linuxetc.co.uk> writes:
| Quote: | The closest forges I can think of are South Wales and
Sheffield. This is the UK - a hundred miles is a long way.
|
Heating the platters past the Curie point should destroy any
magnetic info on them. You can probably do that with a propane torch. |
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Al Dykes
Guest
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| Posted:
Thu Nov 24, 2005 1:16 am Post subject:
Re: Coercivity of current HD platters? |
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In article <1132643542.713397.286190@f14g2000cwb.googlegroups.com>,
robertwessel2@yahoo.com <robertwessel2@yahoo.com> wrote:
| Quote: |
Nick Chalk wrote:
Does anyone have an idea of, or references for,
the coercivity of current HD platters?
I'm looking at degaussers for a charity
refurbishing/recyling project, and I've found a
wide variation in the specs of devices claimed to
be able to wipe hard disks. Before we spend UKP 1k
to 2k, I'd like to be sure that the machine will
do the job.
We already use software wiping tools, but need a
device to handle faulty drives. Given the nature
of the project, and the volume of drives, I don't
think physical destruction is feasible.
If you actually degauss a semi-modern hard disk, it will no longer be
usable in any fashion. In short, you will not be able to reformat it,
at least not without proprietary information from the vendor (which
will likely be different for each model of disk drive). And that's the
best case - some drives will require additional external hardware to
low-level format.
So if you're recycling these drives, degaussing is *not* the answer.
On the flip side, if you're destroying the drives, I don't think
*anyone* serious about security will accept degaussing an assembled
drive as secure. Running a HD through a degausser may cause enough
damage to make the drive unusable, but not enough to prevent someone
serious (like the high end data recovery folks) from recovering
significant amounts of data. Some of those folks might accept
degaussing individual platters.
The usual high end solution is to disassemble the drive, and physically
destroy the individual platters and circuit board. Your local foundry
has a furnace that will make short work of both. ;-)
|
I find a sledge hammer applied a few times to a disk drive on the
concrete floor fine and provides some exercise and job satisfaction.
Once the platters are crumpled up nobody's going to invest the time
and money to try to read any data unles you are already on a terrorist
watch list, in which case they've already bugged your computer and
it's too late. :-) :-(
Before you do more than the sledge hammer treatment IMO you need to
look at applicable privacy regulations and ask the owner of the dead
disk what disclosure risk value they put on the data and do no more
than indicated.
back you your original query, the manufacturer's web site will have
the coercivity numbers for yout model. When I've looked I've found the
numbers much higher than any degauss machine I could afford.
If the machine costs $10,000 US I can buy 500 used disks on ebay
for a comparable cost.
Smash any disk you can't wipe.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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Zak
Guest
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| Posted:
Thu Nov 24, 2005 9:16 am Post subject:
Re: Coercivity of current HD platters? |
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Nick Chalk wrote:
| Quote: | Does anyone have an idea of, or references for,
the coercivity of current HD platters?
We already use software wiping tools, but need a
device to handle faulty drives. Given the nature
of the project, and the volume of drives, I don't
think physical destruction is feasible.
|
If your drives have glass platters, it should be possible to destroy
those with a drill press.
Drill through the cover and the drill bit will break the platters.
This should be a very quick operation, I think.
Or send them off to a recycler that handles this kind of material. If
you have enough drives they might even pay shipping.
Thomas |
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robertwessel2@yahoo.com
Guest
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| Posted:
Thu Nov 24, 2005 9:16 am Post subject:
Re: Coercivity of current HD platters? |
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Nick Chalk wrote:
| Quote: | The usual high end solution is to disassemble
the drive, and physically destroy the individual
platters and circuit board. Your local foundry
has a furnace that will make short work of both.
I don't think we have a local foundry - it's all
light industry around here, now.
The closest forges I can think of are South Wales
and Sheffield. This is the UK - a hundred miles is
a long way.
|
You're thinking too big. Your local high school (or trade school) with
a metal shop will have a furnace for melting metals for modest sized
castings. Usually it's a gas fired open furnace with a ceramic
crucible fitted into the top that you dump the pieces of stock (in
school, usually scrap) into. Typical sizes hold between two and ten
kilos of molten aluminum.
So will a large car repair/customization shop, small foundries catering
to artists (although they tend to be picky about contamination in their
crucibles, so you'll have to buy your own), and many shops that do
custom metal work for things like grates and plumbing.
For a modest donation, your typical high school metal shop will be
happy to melt Big Ben for you. |
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Guest
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| Posted:
Thu Nov 24, 2005 9:16 am Post subject:
Re: Coercivity of current HD platters? |
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All this talk about how to destroy disk drives so the information
can't be read any more ... and two obvious solutions have not come up.
#1: Open the drive. It has many fun parts in it, for example the
magnets (which are quite useful around the shop), or the ball
bearings. The platters (once cleaned off) also make for nice mobiles.
Anycase, remove all the parts you want to keep, except the platters.
Then throw theplatters into an acid bath. Now, this sounds terribly
complicated, but it really doesn't require a chemistry lab. Just get
a glas bowl from the kitchen, and a bottle of muriatic acid (HCl) from
a hardware store or swimming pool supply place, put the platters in
the bowl, and pour the acid over them. Do this outside, wear
appropriate safety gear (at the very minimum rubber gloves and safety
glasses), and keep a garden hose handy. Don't do this if you are not
familiar with basic chemistry safety. After a few minutes, the oxide
coating will have been completely removed (and the platters heavily
attacked), and you can rinse the bits off with a garden hose.
#2: I happen to work in the storage systems research department of a
large computer company. This means that I have a lot of computers,
even more disk drives, and occasionally dead disk drives. It also
means that I get more aggravation from storage systems and disk drives
than your average civilian, and often find myself angry at some piece
of hardware. I also happen to be a target shooter. You can see where
this leads: Suspend the offending drive from a string. Step back 25
paces, load 10 FMJ rounds into your H&K or Sig-Sauer or Springfield
etc. pistol, aim, and fire. For more spectacular results (holes
through the drive, instead of a terribly banged up drive), use a
high-powered rifle instead; .223 Remington and 30-06 both yield
satisfactory destruction of the platter (think swiss cheese). I would
not recommend airguns, archery, or .22 rimfires; it makes for good
target practice, but the drive will just shrug those off. Repeat
until your anger at computers in general and disks in particular has
subsided. If 25 yards is not challenging enough, try doing it from
100 yards distance. Again, don't do this if you are not familiar with
gun safety, in particular issues relating to ricochets. Also check
with the range officer first; at most public shooting ranges, even
attempting this operation will get you thrown out.
DISCLAIMER: Both suggestions are given very much tongue-in-cheek. In
many circles, destruction of the platters using acid or high
temperatures is considered the only really safe way of destroying the
information on a disk - but it is best left to people who have
experience with nasty chemicals. The second operation should only be
attempted in an environment where noise is not a problem, where piles
of completely destroyed computer parts can be cleaned up, and where
there is no danger of errant bullets. I once saw the effect of
someone else shooting up a TV, and the amount of broken glas that
needed to be cleaned up was unbelievable - big mess.
--
The address in the header is invalid for obvious reasons. Please
reconstruct the address from the information below (look for _).
Ralph Becker-Szendy _firstname_@lr_dot_los-gatos_dot_ca.us |
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carmelomcc
Guest
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| Posted:
Thu Nov 24, 2005 5:16 pm Post subject:
Re: Coercivity of current HD platters? |
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What you need is this tool at supluscomputers.com
It supports goverment standard forensic erase which is the highest
requirement out side of destroying the drives.
TOL10257 - CSC Portable Pro Drive Service/ Duplication Station
(SDIPROP
· INSTANTLY CLONE ENTIRE HARD DRIVES
· FACTORY TEST SYSTEM ANALYZES DRIVES
· COMBO IDE/SCSI SYSTEM BULK TRANSFERS DATA BETWEEN INTERFACES
· SUPPORTS EVERY INTERFACE: SCA, SCSI, IDE, E-IDE, UDMA, EVEN 2.5"
NOTEBOOK DRIVES!!
· INCLUDES A COMPLETE FACTORY TEST SYSTEM WITH PRINTER PORT
· FORENSIC COPY MODE FOR LAW ENFORCEMENT
· DOD-5220 GOVERNMENT ERASE FUNCTION
· NOW SUPPORTS ATA-6 DRIVES OVER 137GB CAPACITY
· ELIMINATES BAD SECTORS AND RESTORES DRIVE PERFORMANCE
· INCLUDES FREE: SCA ADAPTER, 2.5" NOTEBOOK ADAPTERS, CABLE SET, DATA
RECOVERY TIPS |
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Nick Chalk
Guest
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| Posted:
Sun Nov 27, 2005 11:41 am Post subject:
Re: Coercivity of current HD platters? |
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Al Dykes <adykes@panix.com> wrote:
| Quote: | I find a sledge hammer applied a few times to a
disk drive on the concrete floor fine and
provides some exercise and job satisfaction.
|
Health & Safety, and personal safety, are the
problems with that idea.
We're a homelessness charity - there's only four
staff, everyone else is a volunteer or client. We
like to avoid arming our clients when they're in
the building.
| Quote: | back you your original query, the manufacturer's
web site will have the coercivity numbers for
yout model.
|
Well, Google and the manufacturers' searches are
failing me at the moment. I found a vague FAQ
entry on Maxtor's site, but nothing else concrete.
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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Nick Chalk
Guest
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| Posted:
Sun Nov 27, 2005 11:41 am Post subject:
Re: Coercivity of current HD platters? |
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robertwessel2@yahoo.com <robertwessel2@yahoo.com> wrote:
| Quote: | Nick Chalk wrote:
I don't think we have a local foundry - it's
all light industry around here, now.
You're thinking too big. Your local high school
(or trade school) with a metal shop will have a
furnace for melting metals for modest sized
castings.
|
Thanks for those suggestions - I'll ask around.
| Quote: | For a modest donation, your typical high school
metal shop will be happy to melt Big Ben for
you.
|
The only problem is that we're a charity. Money
happens to other people. :-/
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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Nick Chalk
Guest
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| Posted:
Sun Nov 27, 2005 11:41 am Post subject:
Re: Coercivity of current HD platters? |
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_firstname_@lr_dot_los-gatos_dot_ca.us wrote:
| Quote: | All this talk about how to destroy disk drives
so the information can't be read any more ...
and two obvious solutions have not come up.
.... |
Thanks - that was much enjoyed by the other staff!
Unfortunately, chemicals, blow torches, and
firearms are not the sort of things we can leave
our clients with. We also need something
relatively fast, given the volume of equipment we
process each month.
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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Nick Chalk
Guest
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| Posted:
Sun Nov 27, 2005 11:41 am Post subject:
Re: Coercivity of current HD platters? |
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Zak <jute@zak.invalid> wrote:
| Quote: | If your drives have glass platters, it should be
possible to destroy those with a drill press.
|
Does anyone know how long glass platters have been
used? What was used before glass?
We're currently receiving disks from about fifteen
to three years old.
| Quote: | Drill through the cover and the drill bit will
break the platters.
|
Hmm, might have to experiment with this. I wonder
how hazardous the operation is.
| Quote: | Or send them off to a recycler that handles this
kind of material.
|
Yes, we've been doing that up to now. We'd like to
handle the data destruction ourselves, so that
we're sure it's done properly. There are plenty of
dodgy geezers in the recycling business. :-)
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem. |
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Al Dykes
Guest
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| Posted:
Sun Nov 27, 2005 5:16 pm Post subject:
Re: Coercivity of current HD platters? |
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In article <dmc3mf$82$4@leviathan.linuxetc.co.uk>,
Nick Chalk <nick@linuxetc.co.uk> wrote:
| Quote: | _firstname_@lr_dot_los-gatos_dot_ca.us wrote:
All this talk about how to destroy disk drives
so the information can't be read any more ...
and two obvious solutions have not come up.
...
Thanks - that was much enjoyed by the other staff!
Unfortunately, chemicals, blow torches, and
firearms are not the sort of things we can leave
our clients with. We also need something
relatively fast, given the volume of equipment we
process each month.
Nick.
|
Give them a sledge hammer and instructions to beat on the disk against
a concrete floor until the platters are bent way out of flat.
Will the person that thinks anyone can get any useful data off these
platters afterwords please raise you hand.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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Al Dykes
Guest
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| Posted:
Sun Nov 27, 2005 5:16 pm Post subject:
Re: Coercivity of current HD platters? |
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In article <dmc412$82$5@leviathan.linuxetc.co.uk>,
Nick Chalk <nick@linuxetc.co.uk> wrote:
| Quote: | Zak <jute@zak.invalid> wrote:
If your drives have glass platters, it should be
possible to destroy those with a drill press.
Does anyone know how long glass platters have been
used? What was used before glass?
We're currently receiving disks from about fifteen
to three years old.
Drill through the cover and the drill bit will
break the platters.
Hmm, might have to experiment with this. I wonder
how hazardous the operation is.
Or send them off to a recycler that handles this
kind of material.
Yes, we've been doing that up to now. We'd like to
handle the data destruction ourselves, so that
we're sure it's done properly. There are plenty of
dodgy geezers in the recycling business. :-)
Nick.
|
If a sledge hammer is too exciting for you, a machinist's bench press
with the right punch will do as much damage as you'd like and it moves
slowly enough to be safe, I guess.
http://www.paintain.co.uk/Automo/presses/press04.htm
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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