how does data recovery work?

Question

is the data really "gone" when we delete files (from recycle bin too) or format hard disk?? how is data recovery possible?? if data is still present in the disc? how can we "overwrite" it with other data after formatting the drive? in this sense why can't a drive hold more data than it's actual capacity?

Answer 1

when you delete data it is not removed .
the header file is changed to say you can write here (thus enableing other data to be writen in that space)
so a recovery program returns this header back to say your data is here donnot overwrite

Answer 2

The only True way to overwrite data or destroy it, is to "0" the harddrive, most harddrive manufacturers will have the program to write zero's to the harddrive, thus wiping it slick with no possible data recovery.

Answer 3

Disks are divided in sectors. when we write a file, we write bits in these sectors. Also a few entries in a index are created. When we delete the file, we just delete the entries in the index, the sectors stay the same until they are overwritten by another file.

Answer 4

I found some good info here.