When you first delete a file on a computer, it is moved to the computer’s Recycle Bin or Trash. When something is sent to the Recycle Bin or Trash, the icon changes to indicate it contains files and if needed allows you to recover a deleted file.
Later, when you empty the Recycle Bin or Trash, the icon changes back to an empty trash can and the files are deleted.
Once the file has been deleted, the computer is removing the header to the file on the hard drive. Once the file header is removed, the computer can no longer see the file. The file is no longer readable by the computer. However, the file is still on the hard drive, at least until another file is saved to the same location.
Because the file is technically there, it may be able to be recovered using data recovery software, designed to rebuild the file header and allow the computer to see the file again. This software only works if no other file or data has been saved over the top of the deleted file.
In another point of view,
A file is in two parts:
- A directory entry which records the file name and also contains a list of the blocks on disk which contain the data contents of the file. The operating system then “knows” that these blocks are in use.
- The actual blocks which contain the data contents of the file.
When a file is deleted:
- The list of blocks in the directory entry is marked as “free” and returned to the operating system. The directory entry is deleted, so the file “disappears” from the file system.
- The actual blocks are not touched, so the data contents of the file remain untouched until some other new file overwrites them.