• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

[NEWS] Data Recovery Myths

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

Mr.Guvernment

Member
Joined
Feb 26, 2003
good read

http://www.hardwaresecrets.com/article/245

i do like this part




The “Freeze It’ Myth, The “Heat It” Myth, And The “Firmware” Myth

The freeze it myth is interesting and makes some sense, but the consequences are a disaster!

During the manufacture of a hard disk drive it’s necessary to calibrate the read/write mechanisms so that the heads get correctly positioned over the disk surface at a determined tolerance, in order to allow the heads read and write on the correct tracks without any kind of error.

Some manufactures, in some models and series, record all those parameters in a ROM memory located in the logic board, or a part is recorded in that ROM and another part in an EPROM or some kind of flash memory that’s inside the drive. This explains why many times the simple replacement of a burned logic board for an identical one using the same firmware version doesn’t make the hard drive come back to life: something is wrong on the inside.

There’s also a kind of surface recording that’s made during the manufacturing process, which is called “servo”, that helps the heads to position correctly. Many times that factory magnetic recording is altered by some reason related to the surface material, and the head starts moving back and forth.

Someone suspected it had some relation with temperature effects and decided to freeze the hard drive in the freezer and then run to connect it back to the PC, and bingo! The drive was recognized and worked again... for some minutes. New freezing session and the drive worked for some more minutes, enough to save some megabytes of information. Then the disk stops working for good.

We’ve read in a forum that when we freeze the hard drive, its interior gets “rearranged” and everything goes back where they belong. This information makes some sense, since the retraction of the material due to the low temperature could have helped the read heads find the tracks again, in some cases. But why the drive stops forever?

Because the disk’s magnetic surface was highly degraded and there comes a time when the “freeze/heat” doesn’t work anymore. The result: the few chances of recovering a good part of data have maybe gone to space. Not to talk about the condensation of the air inside the hard disk (yes, the HD has clean air inside it, a filter to prevent impurities, and a dehumidifier sachet). Read our tutorial Anatomy of a Hard Disk Drive to see this.

One more myth “busted”. Regarding the heat it myth, well... I think there’s no need to comment on this, but there are people who commit and support this crime!



Nice to know as well

The Repair Myth

Some professionals or even companies announce that they “repair” hard drives. We know that it’s impossible, because such professionals and companies don’t even have a proper place for doing so.

What they do, in fact, is change the logic board and/or run a program that hides the bad sectors, the famous “bad blocks” (read our tutorial on this subject). Then they give you the formatted hard disk and tell you it’s been “fixed”.


By reading all of this it just seems if your harddrive is dieing, your screwed and it cant be fixed unless you care to dish out a good chunk of cash!
 
Last edited:
Interesting.

The freezer trick works for some older types of drives that suffer from head "stiction" in the parking zone though, the temperature change breaks the head free. Some older ball bearing drives would also respond to heating because the oil on the bearings got old and sticky and the drive wouldn't spin up quick enough to self test okay. Warmed up, the oil is thinner, it self tests and you can get data off it. I'd say most of the old tricks are really only applicable to older drives.

I've had success with many of those methods in years gone by, had a lot of ancient crappy drives to mess around with. Some needed slamming on the desk, some I took apart and poked at :D One 200MB maxtor I took apart and rebuilt inside a clear plastic bag, and it ran for 2 years after that.....

So I wouldn't really call all these tricks myths, it's just you have to understand why they work in some situations and not others. If you don't intend to spend $$$ on professional recovery, you may as well try some of them, just don't expect the pros to have any luck AFTER you've beaten on it :D

There is such a thing as software corruption of a disk BTW, if you get a lot of power failures you can get bad blocks on the disk from those that aren't hardware bad blocks, they just had the formatting corrupted from bad writes at those points. Also some virii were/are known to make fake bad sectors to hide in. So, using a "low level format" or zero fill on drives that are affected by those can in fact cure them.

Anyhoo, prolly just stuff to keep in mind for yourself should you ever need it, don't go telling the n00bs :D

Road Warrior
 
My hdd "died" this morning, I have no backup.... It feels like power isnt getting to it at all...

any ideas? ;/
 
tried it in a few computers now - gonna try it again today in the hope it will come back to life now its been left a while.

it's death is long overdue however, as partly corroded from where i dropped it into water.

It ran for a year like that :D ill try get a pic.

It may work even still...ill try in a bit.

-Webzta
 
Back