Computer & lap top hard disk drives - Data Destruction
When you decide to sell your old computer one of the biggest risks you face is that
some or all of your personal data might get into the wrong hands even when you have
deleted it. It’s a genuine concern that someone else might see your bank details,
passwords, credit cards or other confidential data. What's worse is that 'someone'
may be looking to use your information for criminal gain; to commit identity fraud
or take money from your bank account for example.
When you delete data or files from your computer hard drive it doesn't actually do
anything except flag the file as being in the Windows Recycle Bin so that if you
have deleted them by mistake you can recover it easily.
Aha! But when you empty the Recycle Bin the file is permanently erased from the hard
NO! Although the file appears to have been deleted even a moderately skilled techie
will have no trouble at all restoring the "deleted" file using easily available data
recovery software - of the type which are freely available on the Internet and here's
When you delete files or folders from your computer, nothing is really "removed"
from the hard disk. Instead. What actually happens is the physical space on the disk
that was used by the deleted data is "de allocated" and flagged as available for
other files to use. So until that space is physically overwritten by new data, it
is possible to recover any "deleted" data by using data recovery software or a low
level disk editor.
Even when a drive is re formatted data can still be easily recovered by someone with
the right tools and skills - as many wrong doers find out to their cost when computers
are forensically examined!
The only way to ensure that data is permanently removed, without physically destroying
the hard drive, is to use specialist software which effectively writes new data
over all of the hard drive (usually with random characters or ones & zeros). Physically
destroying the hard drive has one massive drawback - you can no longer re use your
laptop or computer and therefore you render it un saleable.
Whilst a single "pass" or wipe of an entire drive should be sufficient to permanently
erase all data many experts recommend doing multiple passes as there was a theory
that it might be possible, using a magnetic force microscope to minutely examine
each disk sector's magnetic field to determine its previous state. Theoretically
it might be possible - but no one has ever done it - so one wipe should be enough
but if it makes you feel better do more.
At RediVivus we generally do a three or a sometimes a seven times pass just to make
sure that time travellers from the future won't be able to recover your data and
we only use properly UK government (CESG) rated software to do it.