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On 1/31/06, Iain Buchanan <iaindb@××××××××××××.au> wrote: |
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> If you "shred" or "wipe" the data (run random data over the disk many |
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> times, with a bit of magic formulas thrown in) then apparently the FBI / |
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> CIA / KGB / WTFC has a magnetic data recovery tool to see what bit was |
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> written before the current bit (don't ask me how). |
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It works because hard disks are still analog recording devices. The |
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magnetic field used to write the data extends slightly outwards on |
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either side of the track, and thus can record data (although with a |
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much lower S/N ratio) in the space between tracks. If you have the |
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right hardware that can be convinced to read the area between tracks, |
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you have a chance of recovering the data. |
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|
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In fact in recent years manufacturers have nearly reached the limit on |
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how tightly tracks can be squeezed together before they start |
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overwriting each other. This is why laptop drives maxed out at 120G, |
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until Seagate started using 'perpindicular recording'. |
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Since there is so little spacing between the tracks now, I suspect |
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(but can't say for certain) that the chances of recovering data from a |
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modern large (>160G) drive that has been 'shred'ed is pretty much |
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nil, regardless of the amount of money you through at it. |
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|
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-Richard |
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-- |
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