Where do deleted files go? Do they really get deleted and if so, how?
In: 1
Imagine like a giant piece of grid paper. Files are lines written on the paper. At the top of the sheet is a list of what lines are where on the paper.
When you delete something, all the computer does is erase the line at the top of the sheet telling you where to find it. So it’s still there if you went line by line on the giant sheet of paper, but it would take days to find it by searching for it.
But *also* since the bit at the top was erasing, they might reuse that bit of paper next time you make a new file. Since it thinks there’s nothing there. Then it will be gone.
The FBI or whatever has a tool for noticing the faint lines of erased and written over files, but it’s super expensive to do.
They do not actually get deleted, the index to find them gets deleted. Then they are not easy to look up. They are still there and can be printed over by future additions to the computer. This is why they are so easy to recover. Sometimes even written over records are recoverable. The only way to truly delete is destroy the hard drive. Over writing repeatedly makes it harder to recover and the more times over written the harder to recover parts.
Yes and no. Each file has an address of sorts, this lets the computer know there is a file and where to find all the parts of it.( That’s why we used to defragment hard drives, to put all the data of the same file next to each other on the disk.)
Deleted files have that address removed, so the computer doesn’t know it’s a file.
That is the reason there are certain software that can try and recover files.
There are ways to delete files fully, by zeroing out the space where the files exist. You overwrite the areas on the storage with zeros, that way you can’t recover the files.
If anyone knows better please correct me on this.
Files are stored on storage devices like hard drives as a series of ones and zeros. The operating system keeps track of which files are kept on which portion of the storage device, so it knows where to look when you open a file.
Usually, deleting a file just tells the operating system that that space is available on the disc to overwrite. It doesn’t actually remove the ones and zeros that constitute the file.
It is possible to more securely delete a file, which involves overwriting the space where the file was with zeros. Sometimes, for extra security, you will override the file with zeros, then ones, then zeros again, many many times. This ensures that there is no way to tell what state the bits on the storage device were actually in before.
I’ve always imagined it like this:
Have you ever seen those things where it’s iron filings encased in a screen and you use a magnetic pen/stylus to grab the filings and draw things with it? The filings will stay on the screen until you swipe them off; the filings are still in the screen, they’re just not in any kind of configuration, they’re waiting there until the next time you draw something with the magnetic pen to put them in a new configuration. (One example of these devices is an Etch-a-Sketch for those old enough to remember, except here you use dials to magnetize the filings for drawing).
Data on a hard drive works in a similar way. When you “delete” something you’re not actually deleting the “stuff” that made the file, you’re just deleting the configuration they were in to make that file. The “stuff” is still there, it’s just now freed up to be put into a different configuration when you create a new file.
(It goes a little deeper than this, which others have addressed, but this is the basic principle.)
Latest Answers