Recover data from a LLF disk

Hello. I accidently write zeroes on my wd800. The main hdd. I didn't back-up it for long time ago... how can i recover the data? Is there any chance? Any software?
Thanks..

NO any chance........

Did u write the hdd with zeros the whole media meaning 100% . If yes not possible . if no there is a possibility .

If you have filled the disk with zeros then your data is overwritten and does not exist on the disk anymore.

Not even the experts can help you here

Well, there are people out there who can recover data from a single LLF.
This is why DOD std. is LLF x 3. But there is no software that will do this for you. This is done with Magnetic force microscopy! But this is very expensive and unless your data is worth several hundred thousand dollars it would not be worth the cost of service. So unfortunately you don't have any realistic options. Sorry. :cry:

Well, there are people out there who can recover data from a single LLF.

This is not true. There are no people who can recover data from a single LLF/ZeroFill.

Maysoft,

what is with Magnetic force microscopy (MFM) and scanning probe microscopy (SPM) techniques???

I have hared that when a 1 is overwritten by 0 it actually is closer to 0.095
and when 0 is overwritten with 1 it actually is 1.05 this can be used to reverse the data. But I believe this is only done by some gov. agencies and by some scientists. But from my research there are some sicentifical papers out there on recovering from LLF and degaussing. The people out there that can perform such things are not necessary DR Engineers.

Well, there is no way of getting usable data with just MFM. First, these MFM scopes work slow as hell. Second, you then have to somehow imterpret what you've got (well, that is actually doable). There are just so many factors that make this nearly impossible... I am not saying it is impossible at all, but the amount of time&resources needed to accompish that is well beyond the current technical possibilities.

Actually, recovering from degaussing is much easier than from a LLF/Zerofill. :wink:

By the way, who are "those people"? (Hint: government does not use anything like you've mentioned to recover data)

Maysoft,

I agree, it would take a very long time and allot of resources to do.
My point was just that it is possible but not feasible

If I remember correctly some scientists from Georgia Tech Research Institute (GTRI) have done research on this. Also Peter Gutman has written a paper called
Secure Deletion of Data from Magnetic and Solid-State Memory.
which makes references to IEEE and quantum. I am not sure how valid his paper has, some agreed and some criticized it. You are right, most government agencies don't have much of anything as far as Technology goes and actually lag far behind. But there is one agency which has always been way ahead of the game. But of course I can't prove this because that information is highly classified and not available to us. :cry:

But when It all comes down to the facts, I am just a newb.
So Im sure that your understanding of this is much greater then mine :lol:

It's easier said than done...

quasimodo wrote:If I remember correctly some scientists from Georgia Tech Research Institute (GTRI) have done research on this. Also Peter Gutman has written a paper called
Secure Deletion of Data from Magnetic and Solid-State Memory.

This is just a bullshit (commercial) for selling "magic programs for wiping information"

quasimodo wrote:I have hared that when a 1 is overwritten by 0 it actually is closer to 0.095
and when 0 is overwritten with 1 it actually is 1.05

It does not matter
because HDD does not use simple binary writing on the platters

This is just a bullshit (commercial) for selling "magic programs for wiping information"

This may be true, since the research was for a defence contract in regards to jet fighters and if the enemy would be able to retrive data from magnetic media in the jet. :roll:

I really don't know!

But then I must ask myself why DOD insists on several rounds of overwriting sectors, if 1 round is more then sufficient?

It does not matter
because HDD does not use simple binary writing on the platters

Doomer,
could you please explain to me what HDD uses to write to platter?
I tought It was hex, which in it's raw form is binary.

quasimodo wrote:Doomer,
could you please explain to me what HDD uses to write to platter?
I tought It was hex, which in it's raw form is binary.

new HDDs use PRML encoding - http://en.wikipedia.org/wiki/PRML for storing information - this is not a binary information but analog signals

quasimodo wrote:But then I must ask myself why DOD insists on several rounds of overwriting sectors, if 1 round is more then sufficient?

1. most people are stupid, think stereotypes and managable
2. it was very-very-very old standard for wiping information (for floppy and MFM-disks)

Yep, that would definitely make sense for floppies and MFM disks.

Actually several rounds would not be enough since tracks might be shifted - because of mechanical wear and heat deformations. I think the only reliable way of destroying data on a floppy/MFM HDD is to physically destroy it

Doomer,

thanks for the clarification.

Data can only be stored as positive or negative - 0, 1 - binary... on the disk media.

prml, not a method of storing bits, is a method of intrepretation of the positive or negative - 0,1 - binary.... bits stored on the media.

That's what I thought, since bit can either be on or off.
But now Im confused :roll:

coffeebean wrote:prml, not a method of storing bits, is a method of intrepretation of the positive or negative - 0,1 - binary.... bits stored on the media.

this is not true
PRML using for saving physical disk space - you can encode 4 bits in one analog signal of PRML
after you decode PRML - you can get your bits
RTFM