How is it possible to recover data from a formatted hard drive?

[firefox]

I have come accross softwares that can get data even from formatted hard drives. How is that possible ? Formatting a hard disk should erase the data totally by re-orienting the magnetic media . then how is it possible to recover data.

[Moby-Dick]

It depends on the format.

Military spec disc wiping calls for all the bits on the drive to be set to '1' then back to '0' again a minimum of 7 times to ensure no residual signiture.

[oralpain]

Most formatting just sets up the file system and boot sectors then scans the drive for errors. Virtually nothing is overwritten.

[danroyle]

format just wipes the info but leaves a shadow of everything thats on there the police use software to retrieve this info when they confiscate pcs from dodgy people

i use killdisk on mine run it a couple of times takes a few hours but makes most data unretrievable find i get a more stable reinstall of windows if i do this

[dangel]

Common misconception of the Windows format functions is that it wipes all the data. The reality is:

"Format" - literally just marks the files as dead so the space can be reused AND then does a checkdisk across the whole drive. All the data is intact.
"Quick Format" - does exactly the same thing, bar the checkdisk.

Files/partitions marked as dead can be easily recovered with many bits of software - if you throw away a drive either take a hammer to it or use a program that actually erases every sector of the disk several times.

[amjedm]

Files/partitions marked as dead can be easily recovered with many bits of software - if you throw away a drive either take a hammer to it or use a program that actually erases every sector of the disk several times.

Any good recommendations?

Thanks.

[Yellowbeard]

Virtually any program that will overwrite a disk will work. A DOS based utility such as Partition Magic and many disk utilities from the disk manufacturers will "zero" a drive meaning every available bit is overwritten.

[Agent]

Any good recommendations?

Thanks.

IIRC there is some on the UBCD (Ultimate boot CD)

[oralpain]

I currently use IBM/Hitachi and Segate drive.

Both Hitachi's "Drive Fitness Test", and Segate's "DiscWizard" have zero write utilities. All other drive manufactures should have similar programs available from their sites as well.

[Boogle]

I found Darik's Boot and Nuke very effective and easy: http://dban.sourceforge.net/

Just be careful, its easy to wipe every drive attached to the PC.

[Yellowbeard]

I found Darik's Boot and Nuke very effective and easy: http://dban.sourceforge.net/

Just be careful, its easy to wipe every drive attached to the PC.

Boot and Nuke?

That is a VERY funny name

[Boogle]

Boot and Nuke?

That is a VERY funny name

Heh yeah, it boots your PC - then NUKES it

Its good though, because it doesn't just zero the drive. Unfortunately it takes a good 4+ hrs for a relatively secure wipe.

[Hans Voralberg]

I use magnet when I want to rid of a HD, just for fun, stick ten ultra strong earth magnet to it and I doubt you wud ever read anything out of it ever again (at least i cant manage to)