Isn't there a way to set all unused parts of the drive to 0's? B-) On Monday 06 December 2004 08:35 am, Anders Johansson wrote:

On Monday 06 December 2004 16:16, Brad Bourn wrote:

...

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

You might want to have a look at 'wipe', which is on your CDs/DVD. But note that nothing will completely delete your data if someone with enough money wants to get at it. You'd have to physically destroy the drive to ensure it properly

hmm, good point. I guess I just need to be reasonably sure. B-) On Monday 06 December 2004 08:50 am, Jeffrey L. Taylor wrote:

This isn't sufficient for a sufficiently determined and resourceful adversary. E.g. the intelligence services of major countries and corporations.

Magnetic disks are analog, not digital. E.g., setting a bit to 1 then 0 results in a slightly different magnetization levels and spatial patterns than setting it to 0 twice.

Jeffrey

Quoting Brad Bourn :

...

Isn't there a way to set all unused parts of the drive to 0's?

B-)

On Monday 06 December 2004 08:35 am, Anders Johansson wrote:

...

On Monday 06 December 2004 16:16, Brad Bourn wrote:

...

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

You might want to have a look at 'wipe', which is on your CDs/DVD. But note that nothing will completely delete your data if someone with enough money wants to get at it. You'd have to physically destroy the drive to ensure it properly

When i worked a contract for the military years ago they had to cycle 1,s and 0's to mag tapes nine times before unclassifying the media. These tapes had bigger "dots" than modern media, so maybe harder to erase, but we have better detectors now too. I would think that if you dd 0's then 1's 9 times you would more then exceed the technological capabilities of a curious lap top manufacturer employee. I don't know the commands to do that. Charly Baker On Monday December 6 2004 11:11 am, James Knott wrote:

Jeffrey L. Taylor wrote:

...

This isn't sufficient for a sufficiently determined and resourceful adversary. E.g. the intelligence services of major countries and corporations.

Magnetic disks are analog, not digital. E.g., setting a bit to 1 then 0 results in a slightly different magnetization levels and spatial patterns than setting it to 0 twice.

However, each time you overwrite, the orginal data gets pushed further down into the noise, making it more difficult to read. Eventually, a point will be reached, when it's impossible to tell the original data, from the noise. There is IIRC, a specified number of overwrites, with different patterns, so that the disk is considered fully erased.

This looks even better! Thanks Erik B-) On Monday 06 December 2004 09:25 am, Erik Ball wrote:

Check out DBAN (free, posted on sourceforge). http://dban.sourceforge.net/

Write the ISO image to a cd, boot it up, and at the boot: enter dod. This will start a 7 pass DoD grade wipe on the drive.

It is sufficient to say that the data will be 100% irrecoverable for all practical intents.

Erik

James Knott wrote:

...

Jeffrey L. Taylor wrote:

...

This isn't sufficient for a sufficiently determined and resourceful adversary. E.g. the intelligence services of major countries and corporations.

Magnetic disks are analog, not digital. E.g., setting a bit to 1 then 0 results in a slightly different magnetization levels and spatial patterns than setting it to 0 twice.

However, each time you overwrite, the orginal data gets pushed further down into the noise, making it more difficult to read. Eventually, a point will be reached, when it's impossible to tell the original data, from the noise. There is IIRC, a specified number of overwrites, with different patterns, so that the disk is considered fully erased.

On Monday 06 December 2004 09:30 pm, Anders Johansson wrote:

There have been articles written about this. It seems you can never completely delete data stored on hard drives, they claim it is always possible to recover it using magnetic inference analysis of the drive,

But NOBODY has ever publicly demonstrated it beyond a SINGLE overwrite, and even in those cases they were trying to recover a TINY segment of KNOWN content. (They knew what it used to say). Its an urban myth. -- _____________________________________ John Andersen

John Andersen wrote:

On Monday 06 December 2004 09:30 pm, Anders Johansson wrote:

...

There have been articles written about this. It seems you can never completely delete data stored on hard drives, they claim it is always possible to recover it using magnetic inference analysis of the drive,

But NOBODY has ever publicly demonstrated it beyond a SINGLE overwrite, and even in those cases they were trying to recover a TINY segment of KNOWN content. (They knew what it used to say).

Remember the Nixon tapes? A lot of recorded & erased audio was recovered, over 30 years ago.

John Andersen wrote:

On Monday 06 December 2004 06:50 am, Jeffrey L. Taylor wrote:

...

This isn't sufficient for a sufficiently determined and resourceful adversary. E.g. the intelligence services of major countries and corporations.

Aw Jeeze, that this crap again....

Nobody want source code that badly. Why does this bugaboo of national security heroic efforts to painstakingly recover a disk's content bit by bit always rear its head when ever someone talks about erasing a drive?

There isn't one person on this list that has ever seen this done to a drive written over by normal software. Its theoretically possible in a closed lab to recover known contents, but in actual practice it just can't be done. Was that stray bit set by the most previous write, or the second most previous write? Or was it set by the 57th most previous write?

People: Its a myth. Even the NSA does not bother to try to recover fully whiped drives, the cost and time involved renders any data recovered useless. Osama would be 5 countries away by the time you even the first sentence of his email.

Um, are you sure the NSA hasn't tried this? When I worked on a Top Secret project for a defense company, we kept our computers in a special room. When it came time to replace any of the computers, the old computers would be resold, but without the hard drives. The hard drives were taken by courier to an incinerator. I was told that this was because it is possible to recover erased information from the hard drives. And they don't care about Osama - he and his ilk aren't a threat. The fear was that other countries like Russia, China, Great Britain, or France might get a hold of the disks and recover the information. Steve

The only disks recovered are those where the user simple does rm *.* which is simple.

To the OP: Run Wipe and get on with your life. If really paranoid, bet a bigger hammer.

John, On Tuesday 07 December 2004 00:18, John Andersen wrote:

On Monday 06 December 2004 06:50 am, Jeffrey L. Taylor wrote:

...

This isn't sufficient for a sufficiently determined and resourceful adversary.  E.g. the intelligence services of major countries and corporations.

Aw Jeeze, that this crap again....

Nobody want source code that badly.

Except, of course, my source code, which is the most valuable thing ever crafted and stands to make its possessor wealthy beyond the dreams of Avarice. Anyway, another way to think about this is that if such capacity was really available in magnetic media, then drive manufacturers would be exploiting it to extend the working capacity of magnetic disk drives.

...

Randall Schulz

John Andersen wrote:

This is why people go thru my Office Dumpster nightly

Isn't that how Bill Gates got going in computer software? As I recall, he was a dumpster diver, looking for other people's source code.

If I had already deleted the data I wanted to make sure was gone, I would want to set all un-used parts of the drive to 0's. (where the data used to live) because deleting doesn't actually get rid of the data, just the pointer to that data. Then by writing 0's to the unused parts of the drive, your are effectively overwriting what used to be there with non-sense. As another poster pointed out, there seems to be a threshhold that the data is considered un-recoverable, mentioning that for the company he worked for previously, was 9X. The standard for DoD (Deriks Boott & Nuke) I read was 7X. Anyway, I'll be happy with the 2 I have already gotten and seems like the drive is on it's last leg with the 3rd. B-) On Monday 06 December 2004 04:05 pm, Doug McGarrett wrote:

At 08:39 AM 12/6/2004 -0700, Brad Bourn wrote:

...

Isn't there a way to set all unused parts of the drive to 0's?

B-)

On Monday 06 December 2004 08:35 am, Anders Johansson wrote:

...

On Monday 06 December 2004 16:16, Brad Bourn wrote:

...

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

/snip/

I think you have it backwards; what you want to do is set all _used_ parts of the drive to something useless. The convention is to set everything to the letter "e". Once I knew why, but I no longer do. It is probably a succession of 1's and 0's. --doug

Doug, On Monday 06 December 2004 15:05, Doug McGarrett wrote:

...

I think you have it backwards; what you want to do is set all _used_ parts of the drive to something useless. The convention is to set everything to the letter "e".

Isn't it ASCII 'U'? That's the character code that has strictly alternating 1 and 0 bits (specifically, 01010101). ASCII 'e' is hex 65, or 01100101.

Once I knew why, but I no longer do. It is probably a succession of 1's and 0's. --doug

Randall Schulz

Doesn't wipe require that the files are still there? I have already deleted the directory, so I don't have anything left to 'wipe' I've been reading the man, and I don't see a way to have wipe simply write zeros or random data to all unused portions of the drive..... If you overwrite the place were data was stored, there is no way to get the data back, no matter how much resources you have... B-) On Monday 06 December 2004 08:46 am, Jeffrey L. Taylor wrote:

Quoting Anders Johansson :

...

On Monday 06 December 2004 16:16, Brad Bourn wrote:

...

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

You might want to have a look at 'wipe', which is on your CDs/DVD. But note that nothing will completely delete your data if someone with enough money wants to get at it. You'd have to physically destroy the drive to ensure it properly

This is mostly a theoretical objection. After running wipe on a disk with multiple passes, both random and static, it will take the resources of a country or major corporation to recover the data. If your employer allowed you to take the disk out of a secure, shielded area, either it isn't valuable enough to worry about someone circumventing wipe, or some one was fooling themselves of the threat, or you would have been relieved of the computer at gunpoint, or the data has already been copied while you were sleeping or elsewhere.

There are services that will cut up a drive in two or more pieces for $20, IIRC.

Jeffrey

On Monday 06 December 2004 10:32 pm, Anders Johansson wrote: l

...

There are services that will cut up a drive in two or more pieces for $20, IIRC.

I'll do it for 10 with my trusty axe :)

I'll do it for 5 with my 4 lb. hammer:}}} Rich -- Rich Matson Reno, Nv. USA

On Tuesday 07 December 2004 11:04 am, Don Parris wrote:

Didn't Brad say the drive was dying? Can hard drives be brought back to life? I mean, why worry much about a drive that should wind up in the bin to begin with? If it can be refurbished, just tell 'em to make sure it gets donated to a small non-profit org down in Charlotte - we'll see if we can dissect it to cough up your data, aand lay l theories to rest. At the rate I'm going with LAN Admin, I should crack that drive by AD 3004. :)

heheheh Yes, the drive is dying. I have in the past been able to bring dead drives back to life for customers if I have a duplicate drive. Sometimes you can swap controller from one drive to another to at least be able to recover data to new drive. In any case, the drive I have seems to have some bearing platter problems. If it spins up and I don't move the laptop, it will say spinning(If it spun up at all) If I move the laptop at all it will start making noise like an electric shaver (or yetti from the AOL commercial, heh). And if you leave it powered off long enough for it to cool, won't spin up at all. Definitely a chance for a tech to "check it out" if curiosity kills the cat. No matter, as I have successfully ran the Darik's Boot and Nuke twice. I'm satisfied with that. B-)

On Tuesday 07 December 2004 21:35, John Andersen wrote:

On Tuesday 07 December 2004 09:05 am, Brad Bourn wrote:

...

Yes, the drive is dying.  I have in the past been able to bring dead drives back to life for customers if I have a duplicate drive.  Sometimes you can swap controller from one drive to another to at least be able to recover data to new drive.

But that costs more than a new drive. They want the drive back just to be sure you really had one and were entitled to a replacement.

Swack it with a big hammer, it makes no difference to them. There's no way they would use a used drive.

Pardon my ignorance if this isn't a correct thing that might help or it's already been discussed, but doesn't SpinRite from Steve Gibson's site do this kind of thing...fix a dying hdd enough to recover stuff? http://www.grc.com/sr/spinrite.htm

Not to give Gibson Credit, but to take away M$'s If Gibson's software is willing to try more than once and/or not fail out of a copy if it can't read a sector, and be able to continue on at least getting what it can, this is already a BIG improvement over what windows does/can do. That being said, use of a real OS like GNU/Linux can get you even better results that Gibson's software. For the laymen, there is a value. Assuming they don't know about ubcd and the like. ehehehe There isn't anything more annoying than to try to do a backup in exploder, and have it error out somewhere in the middle and just stop, not knowing where it left off. If your forced to use that machine (for a client or something) the best you can do is xcopy /s/e/c/h/y..... Even when I was still nieve enough to use M$ crap, pkzip did a better job than copy or xcopy (back in the DOS days) for backing up dying harddrives. B-) On Wednesday 08 December 2004 03:17 pm, John Andersen wrote:

On Wednesday 08 December 2004 12:02 am, John B wrote:

...

On Tuesday 07 December 2004 21:35, John Andersen wrote:

...

On Tuesday 07 December 2004 09:05 am, Brad Bourn wrote:

...

Yes, the drive is dying.  I have in the past been able to bring dead drives back to life for customers if I have a duplicate drive.  Sometimes you can swap controller from one drive to another to at least be able to recover data to new drive.

But that costs more than a new drive. They want the drive back just to be sure you really had one and were entitled to a replacement.

Swack it with a big hammer, it makes no difference to them. There's no way they would use a used drive.

Pardon my ignorance if this isn't a correct thing that might help or it's already been discussed, but doesn't SpinRite from Steve Gibson's site do this kind of thing...fix a dying hdd enough to recover stuff? http://www.grc.com/sr/spinrite.htm

Its mostly crap. Software can not fix hardware faults.

Had a guy insist I try it on his drive that was in for maintenance.

I told him it was a waste of time and money, that no software can fix hardware and that his drive was die for reasons un related to the corruption Spinrite can fix. But he purchased it anyway, and the drive was Still dead.

There is nothing spinrite that is not already built into even lame windows 98 utilities.

Like most of Gibson's stuff, its a huge fraud. But you'd never get the idea there was any drive in the world that it couldn't fix by reading Gibsons site.

John Andersen wrote:

There is nothing spinrite that is not already built into even lame windows 98 utilities.

Like most of Gibson's stuff, its a huge fraud. But you'd never get the idea there was any drive in the world that it couldn't fix by reading Gibsons site.

Are you talking about http://grc.com/ vs http://grcsucks.com/ ? :-) -- Marcos Lazarini

On Monday 06 December 2004 9:49 am, Brad Bourn wrote:

maybe something to fill up the unused space with anything, forcing an overwrite where data was once stored.

Is there a fill type program?

B-)

The Ultimate Boot CD at http://www.ultimatebootcd.com/ has some disk wipe utilities. They don't care what's on the drive and they'll 'wipe' all of it by writing whatever pattern you decide on and however many times you want it written/erased. Usually ten passes of all 1s or 0s will be enough for your garden variety disk forensics. Since the HD is dying it may not survive another boot to start these programs... But like the others have said. Anyone that has the money, time and technology to recover whatever was written on the disk will probably recover all of the information. Putting it through a metal shredder and melting the remains to a blob of slag will probably secure your data. Some people also like to use old hard drives for target practice. There are stories that even with a bullet hole through the platters information can still be retrieved from them. Stan

Anders Johansson wrote:

On Monday 06 December 2004 16:16, Brad Bourn wrote:

...

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

You might want to have a look at 'wipe', which is on your CDs/DVD. But note that nothing will completely delete your data if someone with enough money wants to get at it. You'd have to physically destroy the drive to ensure it properly

Doing that would certainly make for an interesting warranty claim. ;-)

On Mon, 6 Dec 2004 10:04:21 -0600, Richard wrote:

On Monday 06 December 2004 09:16 am, Brad Bourn wrote:

...

I have a new laptop that the harddrive is dying on.

I have a warranty replacement on the way.

I have our company's source code on the drive.

I just got the thing to boot (probably for the last time)

Is there a simple command I can run to make sure that the data on the drive after I delete the source code dir is completely gone?

Pass a BIG magnet over the platters! If it's as near dead as it appears, running a wipe program is probably out of the question. Since you probably have to return the thing in some reasonable shape, crushing and cutting are not options. ra -- Old age ain't for Sissies!

They actually sell magnets do that. Now guess at the cost..... . . . . . . . . . . . . . . . I've heard $15,000 US. Pretty much any of the other solutions is more cost effective than that. What we do is dissemble the drive, remove the platters from the spindle and cut them into several pieces. I'm sure there are government agencies that could put most of it back together, but we just don't care that much. Greg

Doug, On Monday 06 December 2004 15:00, Doug McGarrett wrote:

...

You could always take the drive out, take the screws out of it, and break the disk(s) inside, if you're really paranoid about the data.

Presumably a functioning mass storage device is part of the value of the computer system being sold. If you're going to render the hard disk permanently non-functional, you might as well remove it entirely. Presumably (again), the sale being made is of a fully functional computer. This behooves the seller to find an effective way to erase the data without destroying the hardware itself.

Your company should absorb the cost, if the the PC outfit gets upset about not getting the old drive back.

Then that should be done in advance, not as some kind of "bait-and-switch" tactic in which the seller represents the system as one with an intact disk but which is delivered in an irretrievably damaged condition.

For Dos and Windows FS's there are several programs that promise to write eeeeeee...all over the disk, but I'm not sure that you can do that in Linux. Someone will know. . . .

Too late. They've long since weighed in with a variety of viable solutions.

--doug

Randall Schulz