Coercivity of current HD platters? - Storage

This is a discussion on Coercivity of current HD platters? - Storage ; 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 ...

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Thread: Coercivity of current HD platters?

  1. Coercivity of current HD platters?

    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.


  2. Re: Coercivity of current HD platters?


    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. ;-)


  3. Re: Coercivity of current HD platters?

    robertwessel2@yahoo.com
    wrote:
    > 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.

    > So if you're recycling these drives, degaussing
    > is *not* the answer.


    We want to recycle, not refurbish, them.

    > 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.

    > 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.


  4. Re: Coercivity of current HD platters?

    Nick Chalk writes:
    > 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.

  5. Re: Coercivity of current HD platters?

    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

  6. Re: Coercivity of current HD platters?


    Nick Chalk wrote:
    > > 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.


  7. Re: Coercivity of current HD platters?

    Nick Chalk wrote:
    > 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

  8. Re: Coercivity of current HD platters?

    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


  9. Re: Coercivity of current HD platters?

    Al Dykes wrote:
    > 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.

    > 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.


  10. Re: Coercivity of current HD platters?

    Zak 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.

    --
    Nick Chalk ................. once a Radio Designer
    Confidence is failing to understand the problem.


  11. Re: Coercivity of current HD platters?

    _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.

    --
    Nick Chalk ................. once a Radio Designer
    Confidence is failing to understand the problem.


  12. Re: Coercivity of current HD platters?

    In article ,
    Nick Chalk wrote:
    >_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.

  13. Re: Coercivity of current HD platters?

    In article ,
    Nick Chalk wrote:
    >Zak 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.

  14. Re: Coercivity of current HD platters?

    In article <43857e72$0$31280$6c4159fb@news.tweaknews.nl>,
    Zak wrote:
    >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.


    A heavy duty nail gun might also do the trick.
    --
    Jim Prescott - Computing and Networking Group jgp@seas.rochester.edu
    School of Engineering and Applied Sciences, University of Rochester, NY

  15. Re: Coercivity of current HD platters?

    In article ,
    Jim Prescott wrote:
    >In article <43857e72$0$31280$6c4159fb@news.tweaknews.nl>,
    >Zak wrote:
    >>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.

    >
    >A heavy duty nail gun might also do the trick.




    This huy finds a *sledge hammer* too dangerous for his
    people to use.

    Using a nail gun in this fashion is downright dangerous and an
    incorrect use if a dangerous tool.

    --
    a d y k e s @ p a n i x . c o m

    Don't blame me. I voted for Gore.

  16. Re: Coercivity of current HD platters?

    Nick Chalk wrote:

    > 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.


    Wel, if you can't find anything better and the data is not _that_
    critical, you could destroy the printed circuit board of the drive. Kick
    off some components with a screwdriver (make sure it is clearly visible)
    and send the drive off to a metals recycler. The broken board will make
    sure the drives cannot be sold as "not tested" but only as scrap.

    This could be enough prevention for your average drive of unknown origin.

    Or to continue on the press idea: fit out a vise with a block on one
    side. If you learn where to punch the lid this can be a very safe
    process, and again is is easy to see that the drive is useless.


    Thomas

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