Hi all
What is the best practice to remove all data in the disk?
ls fdisk ok or use dd
Can data be recovered?
and what is the dd command?
Thank you
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Greetings,
On Thu, Mar 4, 2010 at 6:31 PM, chloe K chloekcy2000@yahoo.ca wrote:
Hi all
What is the best practice to remove all data in the disk?
ls fdisk ok or use dd
Can data be recovered?
and what is the dd command?
fdisk just repartiions the disk.
dd is an axe. It can be used to copy anything to anything. This is useful to _really_ wipe data off.
Regards
Rajagopal
On Thu, Mar 4, 2010 at 1:01 PM, chloe K chloekcy2000@yahoo.ca wrote:
What is the best practice to remove all data in the disk?
If you want to securely remove the data, I recommend using a tool like DBAN. If you want to just wipe out the partition & boot sector for a clean reinstallation, dd'ing the disk with zero for a couple of Mbytes is more than enough.
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On
Behalf
Of Hakan Koseoglu Sent: Thursday, March 04, 2010 2:54 PM To: CentOS mailing list Subject: Re: [CentOS] help fdisk and dd
What is the best practice to remove all data in the disk?
If you want to securely remove the data, I recommend using a tool like
DBAN.
If you want to just wipe out the partition & boot sector for a clean reinstallation, dd'ing the disk with zero for a couple of Mbytes is more than enough.
I second that. Dban is the niftiest thing since sliced bread. Very handy tool, if a bit slow. But I guess that comes with the territory. 8-)
From: chloe K chloekcy2000@yahoo.ca
What is the best practice to remove all data in the disk? ls fdisk ok or use dd
Maybe something like (replace the ?): - fast but not secure: dd if=/dev/zero of=/dev/?d? bs=4096 - slow but more secure: dd if=/dev/zero of=/dev/?d? bs=4096 - n times slower but n times more secure: for ((i=1; i<=n; i++)); do dd if=/dev/zero of=/dev/?d? bs=4096; done
JD
John Doe wrote:
From: chloe K chloekcy2000@yahoo.ca
What is the best practice to remove all data in the disk? ls fdisk ok or use dd
Maybe something like (replace the ?):
- fast but not secure: dd if=/dev/zero of=/dev/?d? bs=4096
- slow but more secure: dd if=/dev/zero of=/dev/?d? bs=4096
What is the difference between the above two commands? Did I miss something?
- n times slower but n times more secure: for ((i=1; i<=n; i++)); do dd if=/dev/zero of=/dev/?d? bs=4096; done
I don't know what "n times more secure" means. Could you please explain? Does that mean that, with n times as much work, one can still recover the information?
Mike
From: Mike McCarty Mike.McCarty@sbcglobal.net
What is the difference between the above two commands? Did I miss something?
See my second post where I replaced zero by random...
I don't know what "n times more secure" means. Could you please explain? Does that mean that, with n times as much work, one can still recover the information?
That was (still is?) the case... They say that nowdays once is enough... And I guess the NSA and co. would like us to believe that... muahahahaaa!!!! ^_^ If the DoD "considers overwriting acceptable for clearing magnetic media _within the same security area/zone_", there must be a reason. But yeah, I tend to be a little paranoid most of the times...
JD
Hi all
What is the best practice to remove all data in the disk?
ls fdisk ok or use dd
Can data be recovered?
and what is the dd command?
Thank you
Default with boot and nuke is three (or is it four?) passes, but you can tell it full US DoD seven passes, which meets all US gov't requirements for data destruction, and no, you can't get it back.
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
mark
m.roth@5-cent.us wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
Mike
m.roth@5-cent.us wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"
m.roth@5-cent.us wrote:
I wrote
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"
I belive modern discs are brittle, and will shatter, not bend. Thermite would certainly do the trick. Might get you in trouble with local hazard control laws, though. It might melt concrete, so don't do it on your driveway.
Mike
m.roth@5-cent.us wrote:
I wrote
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"I belive modern discs are brittle, and will shatter, not bend. Thermite would certainly do the trick. Might get you in trouble with local hazard control laws, though. It might melt concrete, so don't do it on your driveway.
Bucket full o' sand - that's what they used the last day of my 11th grade chem class, lo, these many years ago. <g>
mark
m.roth@5-cent.us wrote:
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
in the 80s, disks held 10-20MB per 5.25" platter. now they hold 300MB per 2 or 3" platter. in the 80s, bits were written with simple MFM NRZI type recording techniques and the tracks were at absolute locations. Today, the data is written with high density predictive RLL techniques and embedded servo
that said, my work has a policy of shreading/chipping/incincerating all old media. any other sort of erasure/clearing is far too time consuming and labor intensive. the old tapes, drives, etc are stored in a secure room, and once in awhile a data destruction truck comes by, and its all tossed into a giant chipper and comes out as ground scrap metal.
<m.roth@...> writes:
m.roth@... wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"
Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Cheers, Dave
On Fri, 2010-03-05 at 22:33 +0000, David G.Miller wrote:
<m.roth@...> writes:
m.roth@... wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
---- Since most are about 5" x 3-1/2" that makes a perfect MOA target at 1000 yards with 165gr 308. It just goes into pieces of dust.
John
on 3-5-2010 3:03 PM JohnS spake the following:
On Fri, 2010-03-05 at 22:33 +0000, David G.Miller wrote:
<m.roth@...> writes:
m.roth@... wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Since most are about 5" x 3-1/2" that makes a perfect MOA target at 1000 yards with 165gr 308. It just goes into pieces of dust.
John
Gonna be hard to SEE a hard drive with the Garand's iron sights at 1000 yds, much less HIT one.
On Mon, Mar 15, 2010 at 3:33 PM, Scott Silva ssilva@sgvwater.com wrote:
on 3-5-2010 3:03 PM JohnS spake the following:
On Fri, 2010-03-05 at 22:33 +0000, David G.Miller wrote:
<m.roth@...> writes:
m.roth@... wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"
Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Since most are about 5" x 3-1/2" that makes a perfect MOA target at 1000 yards with 165gr 308. It just goes into pieces of dust.
John
Gonna be hard to SEE a hard drive with the Garand's iron sights at 1000 yds, much less HIT one.
With no offense to those involved, I feel compelled to point out that reading this from the top down is a perfect example of what's wrong with top-posting....
:-)
Cheers!
mhr
MHR wrote:
On Mon, Mar 15, 2010 at 3:33 PM, Scott Silva ssilva@sgvwater.com wrote:
on 3-5-2010 3:03 PM JohnS spake the following:
On Fri, 2010-03-05 at 22:33 +0000, David G.Miller wrote:
<m.roth@...> writes:
m.roth@... wrote:
[...]
> Alternatively, the answer on another techie mailing list I'm on is that > you could disassemble the disks and use thermite. > Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Since most are about 5" x 3-1/2" that makes a perfect MOA target at 1000 yards with 165gr 308. It just goes into pieces of dust.
John
Gonna be hard to SEE a hard drive with the Garand's iron sights at 1000 yds, much less HIT one.
With no offense to those involved, I feel compelled to point out that reading this from the top down is a perfect example of what's wrong with top-posting....
:-)
Cheers!
mhr _______________________________________________
Methinks MHR makes a very good point. Reading through all this 'may' be interesting to those of us taken to destroying old hardware by fun means, it seems hardly on point to those looking for some real info on 'fdisk and dd'. Bottom posting hardly helps the situation. IMHO.
EW
MHR wrote:
With no offense to those involved, I feel compelled to point out that reading this from the top down is a perfect example of what's wrong with top-posting....
no. it is a perfect example of posting without editing what you're replying to.
On 3/15/10, Scott Silva ssilva@sgvwater.com wrote:
on 3-5-2010 3:03 PM JohnS spake the following:
On Fri, 2010-03-05 at 22:33 +0000, David G.Miller wrote:
<m.roth@...> writes:
m.roth@... wrote:
[...]
Alternatively, the answer on another techie mailing list I'm on is that you could disassemble the disks and use thermite.
Just a hammer, no need to disassemble the case.
I dunno, a buddy who was in army intel back in the early eighties told me, about 10 years ago, that they could flatten out the platters and read some data. Thermite not only melts the platters, but will hit the Curie point.
mark "and make nice flames and melting metal"Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then
take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Since most are about 5" x 3-1/2" that makes a perfect MOA target at 1000 yards with 165gr 308. It just goes into pieces of dust.
John
Gonna be hard to SEE a hard drive with the Garand's iron sights at 1000 yds, much less HIT one.
Yeap, to bad it has Open Sights on it. That's a bummer.
John
On Fri, 5 Mar 2010, David G. Miller wrote:
Over the years I've ended up with a pile of old hard drives. Some are unreliable; some won't even spin up and some are just REALLY old (e.g., 100s of MB size). I also inherited a couple of rifles (M-1 Garand and M-1 Carbine). I'm thinking write /dev/urandom to ones that will spin but then take the whole lot out in the country for some target practice. It may be possible to scape a little data off of what's left after the drive gets hit with a round from the Garand but I doubt if anyone will want to go to the trouble. It could also be fun.
Or, donate the drives and a cheap torx driver to the educational charity of your choice. Kids *love* taking them apart, and the magnets are quite useful!
Paul Heinlein wrote:
Or, donate the drives and a cheap torx driver to the educational charity of your choice. Kids *love* taking them apart, and the magnets are quite useful!
hah, I have some magnets from some old 5.25" ESDI server drives on my fridge at home. one of them easily holds a really thick calendar to the fridge, you have to be careful, those buggers can pinch you hard.
----- Original Message ----
From: Paul Heinlein heinlein@madboa.com To: CentOS mailing list centos@centos.org Sent: Fri, March 5, 2010 8:16:19 PM Subject: Re: [CentOS] help fdisk and dd
Or, donate the drives and a cheap torx driver to the educational charity of your choice. Kids *love* taking them apart, and the magnets are quite useful!
HD magnets are great. Those are one of the few things strong enough to keep my 2-year old son from opening doors and drawers :)
Fer
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