Random Question....

I guess this is more of a how a computer works question, but why is it that a simple right click delete and emptying the recycle bin dosen't fully get rid of a file. I have deleted gigs of information using that technique and if that doesn't really delete it, where does all the information go?

 

It just deletes the file entry but the file really exists.Of course it might be over-written by another file, but the "un-delete" utilities can retrieve lots of them.

 

AFAIK here is is what happens when you delete a file. The file will disappear from "normal" viewing and accessing in windows. However behind the scenes the file is still on the hard drive and can as mujtaba explained be recovered by file recovery programs until the space which the file occupies is overwritten by something. This is possible because the file's location is marked for deletion in the master file table (MFT) but until something else is stored on the hard disk and that part of the MFT is updated (with the new file details), the old deleted file is still on the drive, and master file table and can still with the right tools be retrieved.

 

Or in other words, a file system basically consists of a "table of contents" listing the locations of each file, and then a huge storage area where the actual file contents are placed.
When you need a file, you look through the table to find the position, which points to somewhere in the storage area.
When you delete a file, you only remove its entry from this table. So if I look for the file, I won't find it because it isn't in the table any longer. It's been deleted. The actual file contents though? What should we do with them? It's just an area on the harddrive, so we can hardly "remove" it. Sure, we could set it to all 0's, but basically, why bother? The area is no longer marked as "in use" because there's nothing in the table pointing to it, so it'll get overwritten the next time we put a file there. So why not just leave the actual *contents* unchanged? Saves time. (It means you can delete a 4GB file instantly because all we need to do is remove the entry from the table, without having to do anything to the 4GB of actual data)

 

Thanks for the info, but I know have a few more questions. Once the file is overwritten does that mean the old file (the one the has be written over) is gone or can it sill be retrived. Also b/c only the "table of contents listing" is deleted and info is always being overwritten does that mean it is a good idea to reformat every few years or so?