Rmoving personal HD data

GraemeUK · 25 Nov 2008 at 18:24

Minority said:
Care to explain that statement? It isn't easy at all.

It's possible to recover data from a drive that has been zeroed because writing a zero to a location on the drive reduces the magnetisation of that small bit of material to almost (but not quite) zero. E.g. suppose that a "1" is represented by a magnetisation of 5.0 (in some arbitrary units) and a "0" is represented by a magnetisation of 0.0.

When you write a "0" where there used to be a "1", the magnetisation might end up as 0.0001 instead of exactly 0.0
The normal disk drive software will recognize 0.0001 as close enough to 0.0 (since it only has to decide if it is closer to 0.0 or to 5.0) but special software and sensitive equipment can detect the precise patterns of magnetisation and recover the data.

GraemeUK · 25 Nov 2008 at 18:30

wush said:
How would you go about doing it then?

If the value of the data demands this method, then choose the 7 pass wipe as stated previously:

Kawolski · 25 Nov 2008 at 19:33

Anybody suggest a good DoD wipe app?

Cybertronic · 25 Nov 2008 at 20:10

Disk Utility

Feek · 25 Nov 2008 at 20:27

GraemeUK said:
It's possible to recover data from a drive that has been zeroed because writing a zero to a location on the drive reduces the magnetisation of that small bit of material to almost (but not quite) zero. E.g. suppose that a "1" is represented by a magnetisation of 5.0 (in some arbitrary units) and a "0" is represented by a magnetisation of 0.0.

When you write a "0" where there used to be a "1", the magnetisation might end up as 0.0001 instead of exactly 0.0
The normal disk drive software will recognize 0.0001 as close enough to 0.0 (since it only has to decide if it is closer to 0.0 or to 5.0) but special software and sensitive equipment can detect the precise patterns of magnetisation and recover the data.

I can't argue with this at all, but it's hardly 'easy' is it?

GraemeUK · 25 Nov 2008 at 20:31

Feek said:
I can't argue with this at all, but it's hardly 'easy' is it?

I suppose it's easy if you know what you are doing (which is why I said it). But for your regular Joe, no. That's really why I said depending on the data value should determine how you erase.

Kawolski · 25 Nov 2008 at 20:32

Cybertronic said:
Disk Utility

I realised my faux pas shortley after my post.
Go easy on me guys I only broke my mac cherry 4 weeks ago.

RoleyBirkin · 25 Nov 2008 at 21:03

Thread seems to be loosing its way sadly.

So lets reiterate the question that still stands:

RoleyBirkin said:
So what about Office?

And where's that 'empty trash securely' option above(red arrow)?

Kawolski · 25 Nov 2008 at 21:10

RoleyBirkin said:
And where's that 'empty trash securely' option above(red arrow)?:

Finder>Preferences>Advanced

likwid · 25 Nov 2008 at 21:17

RoleyBirkin said:
And where's that 'empty trash securely' option above(red arrow)?:

It couldn't really be any clearer.

iSam · 25 Nov 2008 at 21:46

likwid said:
It couldn't really be any clearer.

You are charming!

RoleyBirkin · 25 Nov 2008 at 22:30

likwid said:
It couldn't really be any clearer.

UNHELPFUL (As with most sarcasm)

Kawolski said:
Finder>Preferences>Advanced

HELPFUL

And the Office question?

Minority · 25 Nov 2008 at 23:32

GraemeUK said:
It's possible to recover data from a drive that has been zeroed because writing a zero to a location on the drive reduces the magnetisation of that small bit of material to almost (but not quite) zero. E.g. suppose that a "1" is represented by a magnetisation of 5.0 (in some arbitrary units) and a "0" is represented by a magnetisation of 0.0.

When you write a "0" where there used to be a "1", the magnetisation might end up as 0.0001 instead of exactly 0.0
The normal disk drive software will recognize 0.0001 as close enough to 0.0 (since it only has to decide if it is closer to 0.0 or to 5.0) but special software and sensitive equipment can detect the precise patterns of magnetisation and recover the data.

You are quite correct in your technical explanation, but I am correct - it is far from easy. It isn't even easy if you know what you're doing.

RoleyBirkin · 26 Nov 2008 at 16:15

RoleyBirkin said:
And the Office question?

Which still stands...

likwid · 26 Nov 2008 at 16:28

Man, seriously. Why not use a search engine? Even if someone here did answer you there's a good chance they wouldn't really know what they were talking about.

As far as I know all personal data is stored in your user account which you could remove when you pass on the machine. Again though I'm not sure and if were important to me, I'd look it up.

http://www.microsoft.com/mac/help.mspx

RoleyBirkin · 26 Nov 2008 at 16:53

I've googled this(overall goal) to death and the forums, with the general consensus being re installation of Osx.
Before going down this road, I want to be certain there's no less arduous method of achieving the goal. I'll take on board most things.

likwid · 26 Nov 2008 at 18:04

I really don't see why you would need to reinstall.

Assuming you don't work for the government or have child porn on your computer, deleting your user accounts will be sufficient.

RoleyBirkin · 26 Nov 2008 at 19:27

No re-installation is fine by me!, I'd much rather not.

If user account deletion removes all email, bank information ect, that works for me.