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"Darren New" <dne### [at] san rr com> wrote in message
news:4863d6fc$1@news.povray.org...
>
> I gave him more credit than to complain about it without having actually
> erased the drive. :-)
Maybe I'm too used to idiots. If someone says they've erased a file, I
assume that was just a delete until informed otherwise
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"Orchid XP v8" <voi### [at] dev null> wrote in message
news:4863d8d1$1@news.povray.org...
> Darren New wrote:
>
> > Depends how erased it is, of course. Your boss might not know that you
> > know how to erase a drive correctly. :)
>
> My boss might not know that there's more than one way to "erase" a drive.
>
> OOC... how much does it cost to recover data from a drive that has had
> zeros written to every single byte on the drive? Any estimates?
LOTS. Even recovering from logical failure is Expensive.
I investigated drive recovery after a damaged partition table and a defrag
shuffles sectors of one partition over a second parition. Even to recover 2
directories was far more than I could afford
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Darren New wrote:
> It depends how you erased the drive. If you just formatted it, no, the
> data's all still there. If you actually overwrote it, it takes special
> electronics to retrieve it if you can at all.
I'm told if you take the drive apart, you can take advantage of slight
tracking errors in the read/write heads that allows traces of old
signals to remain present at the margins of each track. However, this is
NOT a cheap operations AFAIK. (!!) It requires clean-room conditions,
sophisticated magnetic scanning microscopes, detailed knowledge of HD
construction, etc.
> If you're the DoD, and large numbers of people die when a foreign
> government spends several millions of dollars to recover the data from
> the disk, yes, 21 passes is probably good. That, or scrubbing the drive
> with a belt sander or wire brush and then soaking it in acid until it
> dissolves.
...or just incinerate the platters? (Heat tends to disrupt magnetic
domains rather efficiently - as does the platters being reduced to
molten glass and deformed beyond recognition!)
Anyway, hypothetically supposing somebody magically recovered every
single file from these drives, they would get... the names of the drugs
we were working on 5 years ago, and possibly some analytical results
data. Which won't mean a damned thing, because they won't know what
"sample 39" actually *is*.
It's more the fact that the drives had licenced software on them that
other people shouldn't have...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Gail Shaw wrote:
> Maybe I'm too used to idiots. If someone says they've erased a file, I
> assume that was just a delete until informed otherwise
Mmm... better to be pleasently surprised than horribly dissapointed? ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> OOC... how much does it cost to recover data from a drive that has had
>> zeros written to every single byte on the drive? Any estimates?
>
> LOTS.
I thought so.
Presumably it's something you only bother doing if the data is worth
more than the cost of recovery...?
> Even recovering from logical failure is Expensive.
> I investigated drive recovery after a damaged partition table and a defrag
> shuffles sectors of one partition over a second parition. Even to recover 2
> directories was far more than I could afford
Ouch.
I always thought this kind of service was only of use to intelligence
agencies and people with poor backup procedures. ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> I'm told if you take the drive apart, you can take advantage of slight
> tracking errors in the read/write heads that allows traces of old
> signals to remain present at the margins of each track.
Yes. That's why the DoD doesn't actually erase disks that contain
*really* sensitive information. Unless you consider a grinding stone
"erasing".
> ....or just incinerate the platters? (Heat tends to disrupt magnetic
> domains rather efficiently - as does the platters being reduced to
> molten glass and deformed beyond recognition!)
No, I believe the actual rule is "grind off the surface, then dissolve
the platters."
> It's more the fact that the drives had licenced software on them that
> other people shouldn't have...
Right. Simple overwriting is enough. Like all security, the point is to
make it more expensive to recover the data than the data is worth.
--
Darren New / San Diego, CA, USA (PST)
Helpful housekeeping hints:
Check your feather pillows for holes
before putting them in the washing machine.
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"Orchid XP v8" <voi### [at] dev null> wrote in message
news:4863dac5$1@news.povray.org...
> Gail Shaw wrote:
>
> > Maybe I'm too used to idiots. If someone says they've erased a file, I
> > assume that was just a delete until informed otherwise
>
> Mmm... better to be pleasently surprised than horribly dissapointed? ;-)
Yup.
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"Orchid XP v8" <voi### [at] dev null> wrote in message
news:4863db04$1@news.povray.org...
>
> I always thought this kind of service was only of use to intelligence
> agencies and people with poor backup procedures. ;-)
Well, seeing as I lost data in the process, I guess that you'd put me in
category 2?
In limited defence, I had a fairly complete backup (DVD) a few months old
and a partial backup a week or so old (flash drive). I only lost a few
things. Most were recreatable.
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> news:4863db04$1@news.povray.org...
>> I always thought this kind of service was only of use to intelligence
>> agencies and people with poor backup procedures. ;-)
>
> Well, seeing as I lost data in the process, I guess that you'd put me in
> category 2?
> In limited defence, I had a fairly complete backup (DVD) a few months old
> and a partial backup a week or so old (flash drive). I only lost a few
> things. Most were recreatable.
Fact: When I was at uni, every single time assignment hand-in date came
around, you would not *believe* how many 3.5" disks went faulty! ;-)
What amused me was the scene that unfolded the other day...
Jane: Hey Andrew, you know that safe you used to use to hold the backup
tapes? You don't need that any more, do you?
Me: ...er, YES.
Jane: Oh. Really??
Me: Um, yes.
Jane: ...Oh. What, even in the new building?
Me: Er, yes.
Jane: Oh. Don't you use DVDs or something now?
Me: ...?
Jane: So I can't have that safe then?
Me: Er, no.
Jane: Oh, OK. Well anyway, it's been moved to the lab now.
Me: ...right, OK. That's a procedure violation then.
Jane: OK. Bye...
Fact: Capacity of a DVD = 4 GB. Capacity of a single DDS-4 tape = 20 GB
= 5 DVDs. Capacity of a single LTO1 tape = 100 GB = 25 DVDs. Transfer
speed of a DVD = 1.35 MB/sec. LTO1 = 15 MB/sec. Why in the name of God
would we use DVDs?!
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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"Orchid XP v8" <voi### [at] dev null> wrote in message
news:4863f9fb@news.povray.org...
> > news:4863db04$1@news.povray.org...
> >> I always thought this kind of service was only of use to intelligence
> >> agencies and people with poor backup procedures. ;-)
> >
> > Well, seeing as I lost data in the process, I guess that you'd put me in
> > category 2?
> > In limited defence, I had a fairly complete backup (DVD) a few months
old
> > and a partial backup a week or so old (flash drive). I only lost a few
> > things. Most were recreatable.
>
> Fact: When I was at uni, every single time assignment hand-in date came
> around, you would not *believe* how many 3.5" disks went faulty! ;-)
We had a simple solution to that problem. Faulty disk = 0%. Suddenly the
disks got more reliable. Must have been a faulty batch.
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