Deleted data restoration
I have heard about softwares which can restore data which has been deleted from your computer.I wanted to know how these software works? And also if there exist some way or some situation of deleting data in which data cannot be recovered by any mean.
Data is stored on a hard drive. There is a table which keeps track of where on the hard drive the data is stored. Typically, "deleting" data actually just removes the record from the table. The data is still where it was, untouched, on the hard drive. Eventually some other data will be written over the top of it.
If you read every bit of space on the hard drive that the table says is empty, you will find the data still there.
If you want it truly deleted, write over it with other data. Repeatedly. And if you really, really, really want to be sure, burn it, shred the ashes, and burn it again.
If you read every bit of space on the hard drive that the table says is empty, you will find the data still there.
If you want it truly deleted, write over it with other data. Repeatedly. And if you really, really, really want to be sure, burn it, shred the ashes, and burn it again.
Last edited on
Yes, in both DOS and Windows, when you delete a file, the system only changes the first character of the filename so that the OS cannot see it any longer as a user file.
MYFILE.TXT would be changed to $yfile.txt
( or similar)
The file is still intact and can be "UnErased" simply by setting the filename back to its original name.
For a second level - more advanced problem,
Some "Undelete" programs actually go looking on your hard drive to find data associated with your deleted file, and actually recreate it and give it a new name - with the same contents of the original.
THIS is the reason that - if you accidentally delete a file- and expect to use this method - then you need to STOP everything. Because by continueing to work on your computer - and especially to SAVE anything on your computer may, and likely will, overwrite part or all of your original file - and therefore ensure that there will be nothing available to be recovered during the "Undelete " process.
For a third level - most advanced problem,
Some hardware devices can actually "Read" ghost images of "Once had been There" 1's and 0's and can , as if by magic, pick up faint images of code that had been well removed and erased.
There are programs on the net that will erase beyond all recovery
- if you search for them.
oh & btw, some programs will use the space "Behind" another file to save a file - so just knowing the name of , or erase the file, may or may not erase the actual file, and inversely deleting the wrong file may in fact, delete another file if that second file is stored within the "Unused" space of the first.
Maybe I ought to explain that a little better.
Your HD is divided into small groups, let's say 512 bites
A program is only 200 bites long
There remains (512 - 200 = 312 bites of unused space
allotted to this file.
Another program "Prog2" , with a size of , say, 256, can be saved and stored within this unused space. (312 - 256 = 56 bites remaining still)
If you were now to delete ( with vengeance ! ) the first file, then you're second one would also disappear ( usually)
You can write these programs in C && C++, and you can learn more by searching the web
MYFILE.TXT would be changed to $yfile.txt
( or similar)
The file is still intact and can be "UnErased" simply by setting the filename back to its original name.
For a second level - more advanced problem,
Some "Undelete" programs actually go looking on your hard drive to find data associated with your deleted file, and actually recreate it and give it a new name - with the same contents of the original.
THIS is the reason that - if you accidentally delete a file- and expect to use this method - then you need to STOP everything. Because by continueing to work on your computer - and especially to SAVE anything on your computer may, and likely will, overwrite part or all of your original file - and therefore ensure that there will be nothing available to be recovered during the "Undelete " process.
For a third level - most advanced problem,
Some hardware devices can actually "Read" ghost images of "Once had been There" 1's and 0's and can , as if by magic, pick up faint images of code that had been well removed and erased.
There are programs on the net that will erase beyond all recovery
- if you search for them.
oh & btw, some programs will use the space "Behind" another file to save a file - so just knowing the name of , or erase the file, may or may not erase the actual file, and inversely deleting the wrong file may in fact, delete another file if that second file is stored within the "Unused" space of the first.
Maybe I ought to explain that a little better.
Your HD is divided into small groups, let's say 512 bites
A program is only 200 bites long
There remains (512 - 200 = 312 bites of unused space
allotted to this file.
Another program "Prog2" , with a size of , say, 256, can be saved and stored within this unused space. (312 - 256 = 56 bites remaining still)
If you were now to delete ( with vengeance ! ) the first file, then you're second one would also disappear ( usually)
You can write these programs in C && C++, and you can learn more by searching the web
Last edited on
@Maschops, as you told me
" if you really, really, really want to be sure, burn it, shred the ashes, and burn it again."
how to do this ?
" if you really, really, really want to be sure, burn it, shred the ashes, and burn it again."
how to do this ?
How to burn it? Get the hard drive, and get a blowtorch, and then apply the lit blowtorch to the hard-drive until it's a melted pile of metal and plastic and silicon.
Oh! I thought its some kind of programming process,done by using some software or something similar. well thanx to both of u for such a brief description.
You could google for "secure file delete" or something like that. But when disposing of a hard drive, it could be time-consuming to do this to the entire drive so physical destruction may be better.
and can someone tell me about DoD and guttman process to delete the file. how do they work????
Topic archived. No new replies allowed.