When you create a file, it has its first bite at existence, an existence which continues until you, in your casual god-like manner, delete it. Deleting the file isn't the end, though. All you need to do is open up the Recycle Bin on your desktop, select the file and drag it onto the desktop or into an Explorer window to recover it. Or simply double-click to open the Recycle Bin, select the file, and choose Restore from the pop-up menu to restore it to its original folder. Voila! Witness the file's second coming.
Now, what happens if you empty the Recycle Bin? Surely that's the end of the file's existence? To all appearances, yes. The file will appear to have been completely annihilated. But that's only because Microsoft reckons once you've deleted a file and emptied the Recycle Bin, you and the file have both had enough chances. But with an undelete utility there's a good chance you can resurrect the file yet again for its third go at life – good news for those of us whose fingers work faster than our brains.
What won't recycle
The Recycle Bin may be a marvel – one which most of us take for granted – but it does have its limits. For starters, the Recycle Bin does not catch every file you delete. All files deleted from the desktop or Windows Explorer end up there, as do files deleted from within compliant programs. Files deleted at the DOS prompt, though, bypass the Recycle Bin, as do any files you delete from removeable media such as floppy or Zip disks, and files deleted from compressed folders.
What's a 'compliant' program? You'll find most reputable commercial programs are compliant. That is, if you delete a file from within one of these programs it will be sent straight to the Recycle Bin, from which you can restore it if you need to.
The only way to check whether a program is compliant is to try deleting a test file, and then look for it in the Recycle Bin:
- Open the application you wish to test.
- Create a test file and save it.
- Use the application's File -> Open command to display the Open dialog box.
- Locate your test file in the list, right-click the file and choose Delete from the pop-up menu.
- Check the Recycle Bin to see whether your file has been placed there.
One thing to watch out for is deleting files via macro languages, such as Microsoft Office's Visual Basic for Applications (VBA). While recent versions of Office are Recycle Bin compliant, if you create Office macros which delete files automatically using the kill [file] statement, those files will bypass the Recycle Bin entirely.
Why files don't disappear
So, what's going on? How is it you can delete a file and yet it remains on your disk?
Let's start by looking at what happens when you delete a file and it's placed in the Recycle Bin.
In fact, the file is not moved to the Recycle Bin at all. Instead, the file stays in the same place but its directory entry – the complete path and filename of the file – is removed and placed in a hidden folder called Recycled. (Note: If you have more than one drive in your computer, you'll have a Recycled folder for each drive.) The file is then renamed. The original name and location of the file are stored in a hidden index file, called INFO2 (or INFO, if you're using Windows 95), located in the Recycled folder.
When you open the Recycle Bin, click a file and choose Restore, the original path is read from the INFO file, the file is renamed and its directory entry restored.
Deleted files are renamed and stored in the Recycled folder, as can be seen in this folder listing displayed in a DOS window. (Click the image to see a full-size screenshot.)
The Recycle Bin is a FIFO stack: First In, First Out. That means the files you delete earliest are emptied from the Bin first. When the Recycle Bin is full, Windows starts deleting files from the Bin to make room for newly deleted files. It's only when you right-click the Recycle Bin and select Empty Recycle Bin from the pop-up menu that all files within the Bin are 'deleted'.
As you can see, files aren't really erased when you delete them, just renamed and their location hidden from view. So, what about when you empty the Recycle Bin? What happens then?
Once again, the file data is not deleted. Instead, Windows changes the file's directory entry to indicate the space occupied by this file is no longer needed and is available for use. The data's still there, but at any time if the operating system needs space for another file, it may be overwritten. Until it is overwritten, the file still exists on the hard disk and is recoverable. That means you dramatically increase the chances of being able to recover a deleted file if you refrain from any subsequent disk activity, such as creating, editing or copying files.