"BUT every single bit transactions are stored in a SECRET, hidden area of the HDD that you can NEVER access...."

Man after a couple of years that secret area must be 20 gig in size. I think I would notice that. Getting deep in here guys

Nope. This subject is simply one of my pet peeves.

It's one of those "common sense" things. If it doesn't make ANY SENSE that something is possible... then it isn't possible.

If you erase a VCR tape, the old image can be PARTIALLY restored. Why/how? Because it's an ANALOGUE signal that was overwritten with an ANALOGUE signal. With good enough equipment and enough time... the old image could be brought up. Not fully detailed, but perhaps outlines. Enough to make it out.

But digital is ON... or OFF. Once you've flipped it, you can't see what it was before.

If there were a reliable way to do this, hard disk manufacturers would have already taken advantage of it to vastly increase the amount of data stored on a disc.

But the simple fact is that there IS no reliable method to do this. Forensic labs COUNT on the fact that people DON'T use methodical wiping methods. There's slack space between files that is almost never filled up, and sometimes they can pull a few K out of those, enough to get an IDEA of what used to be on the drive. But once a data area is overwritten, even once, the odds of being able to reproduce what used to be there... are statistically nil.

Couple years? If that "secret area" really existed, in ONE DAY my hard drive would be petabytes big!

Reading this confirms that relatively easy recovery of overwritten data on hard-drives is a myth. I would simply overwrite the data once and leave it at that.

The techniques described on that page are only used for military and government applications where data recovered - even the smallest amount - could reveal threats to national security. It's not for revealing that someone wiped the company accounts for malicious purposes, or that you've got infringing copies of copyright protected material.

But if it makes you sleep better because your drive has been wiped to some DoD standard that's fine. Bear in mind though, most of the companies selling this type of wiping software prey on the conscience of those who believe the hype that such recovery is possible.

To answer the orginal question. The DOD does something like this. First a pattern.

10101010 first pass
01010101 the complement second pass
00101100 random pattern third pass changes with each write cycle

Nothing getting through all that. If it makes you feel warm and fuzzy do this loop several times in a row. Keep in mind it takes a long time.

US Department of Defense (DOD 5220.22-M) alternating cycle
You can choose to utilize the write method required by the US Department of Defense, which specifies that "hard disk media is sanitized by overwriting with a character, then the character's complement, and then a random character." Note that this technique requires at least three overwrite passes to conclude a full cycle.

Also bear in mind that the DoD invented that method for use on MFM hard drives! Y'know, the kind that shipped with a list of bad sectors hand written on the side?

Modern drives offer FAR less opportunity for data recovery of ANY kind.

I agree: Here is a little link from Seagate. The drives I run.

http://www.seagate.com/support/kb/di...lfmt_what.html

Im sure others offer the same thing

get the mfg's diagnostic disk and just write zero's to the drive, do this like 7x, it's quite effective and good enough

LOL... That's awesome!!

I'm not sure about the legality of the visual that creates, however it does get your point across very well. One that I am in agreement with by the way.

*snicker*

Some people just need to be beaten over the head with... an... udder.

*snicker*

Little do you know there is a secret high capacity memory chip below the platters that can hold well over 20 TB of data at a time....... Once that is fully used it is overwritten.

Well, if you are truely phobic about your HD security, after you're done with it, drill several holes through it with a nice big drill bit and you'll never have to worry about somebody snooping around...sheesh, sometimes I wonder what people have to hide on their HD...nevermind, I'd rather not know

Do you know of any ways I can access that chip on my iPod? That would really be great for storing movies... and I bet battery life would see a significant increase...

That would be cool, 20 TB on a USB keychain drive. I could ditch the buners

I agree the retrieval is usually difficult but I have seen it you'll just have to take my word for it.
There were occasions where nothing of value was recovered as has been pointed out. Word and text files are comparatively easy, however large images are just about impossible.
The evidence you ask for can not be demonstrated on this board and so you will dismiss my word because of your entrenched view and so I will have to leave the discussion there alas.

No, I think there's some middle ground here. We can both agree that simple short text retrieval is possible and perhaps even "easy" (relatively speaking). But that images, movies, or even big data files... especially encrypted or compressed ones... are, for lack of a better term, NEVER COMING BACK.

I saw on TV where a professional data recovery lab claimed they could retrieve data even though it had been overwritten many times. They said it was possible as they *sometimes* found that the tracking was off on the HDD and they could still read the "edge" of the data and it would reveal what had been written prior. I agree that it would be quite a task though and require great expertise to glean any valuable information. Also, they even said the data was incomplete. Still. I thought this was pretty cool. So did the US government.

One suggestion that the gentleman had for making data disappear, for sure, was to place the HDD in your kitchen oven and set it at about 300 degrees f or 350 f, I forget. Anyway, when the disk gets hot enough, it loses it's magnetic properties and then therefore loses all data. Then, (he said) when the disc cooled down, it would get magnetic again! I don' recommend this unless you are throwing out the HDD though.

What I do, if I want to minimize risk of "sensitive" data being retrieved, is after I do a delete process, I simply defrag the HDD a few times. Then, a lot of the clusters are overwritten during the re-organization of the information. You can then for free, download many recovery tools that will allow you to see if you did the job right. Of course, if it shows any info and you want to retrieve it, then you have to buy the proggy. But, this is not our intent. So the whole process is free.

It is VERY important to do something if you ever decide to sell your computer with the HDD in place as it is damn sure easy to recover things if you are not careful. Such as email addresses, credit card numbers, passwords etc. I have even read where folks got thrown in jail after they took their PC in for repair, and the technician saw some stuff that was illegal. He then called the cops!

Gurm: I remember those drives. By todays standards they were a nitemare

Crabby: The magic of TV

Kind of like when QVC shows you that everything they sell actually works

If they want to spend a couple million $$$$ to see "Nurses in Latex" volume 186 Heck ill give them a copy almost for free

Hahahahhahaha! I don't have that one! Yet!!! My favorite porn stars name is Miles...Miles Long. heheheheheheh *coughs*

Modern drives do not have data alignment issues, and the data is packed so tightly on those large-sized platters that any chance of this happening is eliminated.

ESPECIALLY since the most modern drives use perpendicular storage!

ehh, just go to a car junkyard and pay the guy a few bux to use one of those super magnets they use to lift cars, if that don't kill and scramble the info enough, nothing will

The problem of course is then USING the hard drive afterwards. Another reason NOT to use the "oven" method.

Gurm...amen to everything you have posted. Secret areas of the drive ??? Anyone seen my unicorn??? Come on, guys. As Gurm has pointed out, drive data is digital. Once you stuff around with the numeric pattern of the 1 and 0s the data is gone, simple. True, formatting alone does not destroy data, neither will a small number of repeated defrags, but if you run something like Eraser at its full strength (I think it can manage something like 27 passes--correct me if I'm wrong), then the data is gone...destroyed...nada! AND once you have used Eraser, you can go back to using the drive as if nothing happened...no damage. The only drawback, as I pointed out in a previous post is that, at full strength, Eraser can take a day or two to finish the job.
Note to first poster...look at this link: http://www.heidi.ie/eraser/faq.php (Note that this web page is not refering to the freeware software, also known as "Eraser"...it is bought/paid for software... For those wanting to download the Eraser freeware, try here:
http://www.freewareweb.com/cgi-bin/archive.cgi?ID=161 )

you do realise that was a joke right???