A question about "Deleted files" in a computer...

Question

Is it true that even when you "delete" files from your computer, those files even when the trash bin is empty they still exists?

Does this apply to Pc or to Mac?

How exactly that works?

(Explain in simple terms, thanks)

Answer 1

It deletes the inode only, an inode tells the computer where the file is on the disk. So, it will eventually become overwritten, but at first when you delete it the computer just considers it blank space. Imagine a chalkboard that is full of stuff, but you are told that if you need to you can erase some parts of it. You probably won't go through the trouble of erasing it until you need it.

Answer 2

Yes there is still data there. To what extent it can be recovered depends on various things. This is what data forensics is about.

Think of a standard paper file cabinet. Putting a file in the recycle bin is like taking the papers out of the folder they were filed in and putting them in another folder marked 'hold onto these for now'. Now emptying the bin is like just taking them out of the file folder and leaving them in the drawer. They are still there just not filed. Now shove some of the loose papers into the bottom of the drawer because they were in the way of adding a new file folder. etc. etc. After a while some of those old papers are just useless from being crumpled/ripped/etc. but one could probably put together what the contents of the now missing file folder(s) is/are from digging into the bottom of drawer and pulling out the scraps of papers left.

This applies to pretty much any operating system using a standard filesystem.  

Answer 3

Yes.

"A common misconception is that the data is actually removed from the hard drive (erased) when you delete a file. Any time that a file is deleted on a hard drive, it is not erased. Instead, the tiny bit of information that points to the location of the file on the hard drive is erased. This pointer, along with other pointers for every folder and file on the hard drive, is saved in a section near the beginning of the hard drive and is used by the operating system to compile the directory tree structure. By erasing the pointer file, the actual file becomes invisible to the operating system. Eventually, the hard drive will write new data over the area where the old file is located."

There are certain applications you can download that will overwrite certain areas of memory for you, thus 'deleting' them.

Answer 4

In PC, there is a thing call FAT, File Allocation Table.

It is like an address book that it keep record for the operating system to know where the file is located in the hard disk.

When you delete a file, the record on where the file is located are remove so that the operating system have no idea where is it.

The address use by that file are now free for other files to occupy.

The file will be gone if other files overwrite it.

In simple term, it is like you live in room 105. When I remove you, I remove the record that you live in room 105 so that other people can live in your room. You will cease to exist if other people move into your room.