Hard Disk Failure

Ben Scott dragonhawk at gmail.com
Sun Feb 26 19:32:01 EST 2006


On 2/25/06, Jeff Kinz <jkinz at kinz.org> wrote:
> It would actually makes sense for the hard drive internals to be able to
> deliver information about what the analog head reads were seeing to the
> external interface because it would allow the manufacturer/developers,
> or technicians to do really deep, meaningful diagnostics on a drive.

  From what I understand, many drives have additional diagnostics and
commands in addition to the standard "read block X" stuff.  However,
these commands are manufacturer-specific.

> A long time ago, working on a contract for equipment destined to be
> delivered to the NSA I heard a rumor about the procedure that you had to
> go through to remove the hard drive from an NSA building:
>
> Basically the drive was disassembled, the "rust" was sanded from the
> platters, the platters were shredded, and all of the "rust" and shredded
> platter material were placed in a crucible and melted down.the drive can
> now be removed from the building.

  Hard drive platters aren't "rusty" at all; they typically have a
mirror finish.  Perhaps that was a reference to the magnetic coatings
on the platters; while not iron, I can sorta see an analogy there.

  Sanitizing procedures for disks containing TOP SECRET data require
one to obliterate the recording medium.  For hard disks, that means
either sanding down the surfaces of the platters, or melting down the
entire platter.  Shredding doesn't really enter the picture; it's not
required in addition to that, and is not sufficient by itself.

  For lower levels of classified data, one used to be able to use
certified degaussing or software tools.  However, these are becoming
less and less allowed these days -- both storage and recovery
technology has become so sophisticated, and information densities so
high, that it is difficult to be sure everything is gone.  Physical
destruction is becoming the universal requirement.

  Google for "clearing and sanitization matrix" to see some of the
requirements that have been published in the past.

-- Ben



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