What Really Happens When You Press 'Delete'
Tara Taghizadeh -- July 13, 2011
Back in 2000, Sir Paul McCartney's bank data was left on a merchant bank's computer. The machine was then sold without the files or drive being wiped clean. The data was then discovered, and the story ended up all over the news about how this particular bank and possibly others like it were not taking precautions to erase data on old computers, which were later sold or donated.
Forgetting to delete pertinent information from any hard drive is worrisome. Copy machines also pose risks. According to published reports, most copiers installed since 2002 have hard drives that save images of all copied documents. When these machines are then sold or discarded, the stored information, which can include private information such as medical records, frequently remain intact.
What does "delete" mean?
Many users are still convinced that when they delete a document or file on their computer, it vanishes into thin air -- but that's hardly the case.
As "Sam," a security engineer who wishes to remain anonymous because of the nature of his job, explains: "When a user 'deletes' a file, it's not really gone. Deleted files are sent to the Trash folder. At this point, files can still be recovered." However, even if the Trash folder is emptied, it doesn’t mean the file has disappeared completely. "But the longer a deleted file is left on a drive, the greater the chance the file cannot be recovered," Sam says.
Everyday PC maintenance
There are a number of programs out there that help ensure that your deleted files are really deleted. In addition to guarding your privacy by removing traces of your Internet browsing history and files and programs you have used, AOL's Computer Checkup cleans registries, removes clutter by clearing out temporary files, and helps solve the problem of a fragmented hard drive by rearranging data so it can be accessed more quickly.
If you have accidentally deleted files, Computer Checkup Premium also offers an "undelete" function.
Formatting and disk wipe
Then there are times when you really do need to permanently delete everything. If you are in the process of donating or selling your computer, or if you have sensitive information stored on it which you wish to be deleted permanently (such as medical information, bank or legal documents, or Social Security numbers), tech experts recommend reformatting your hard drive or performing a disk wipe.
According to The Tech FAQ, "Formatting the hard drive or any of its partitions will completely erase all data that is present."
A thorough "disk wipe" will essentially overwrite your hard drive to the point where recovery is impossible. As "Sam" explains, "When the U.S. Government wants to delete information from an entire hard drive, it employs the Department of Defense disk wipe, which means the entire drive has its data overwritten with a random pattern of zeros and ones (binary data) three times. At this point, any data on the hard drive is considered unrecoverable. In some instances, the platters are removed from the hard drive and dipped in caustic acid -- referred to as 'erase by physical destruction.'"
Users can (and should) erase the hard drives of their old computers so their data cannot be found by anyone else (think Paul McCartney). One program "Sam" and other tech experts recommend is Darik's Boot and Nuke, which will delete the contents of a hard drive with certainty.
Consequences of not deleting files
Sensitive information carelessly stored on computers can lead to identity theft, and also harks the growing need for computer forensics.
In 2007, for example, a forensics expert found that the new publisher of the Minneapolis Star Tribune had transferred sensitive information over from his St. Paul Pioneer Press computer, where he previously worked. In another case, the insurer Health Net was recently sued as a result of a missing computer hard drive that stored the medical records of several thousand customers.
Deleting files from your computer is similar to shredding documents: Store what you need, and digitally "shred" those you don't. (Source: Lifestore)