So recycling your old computer may be the best option. There is, however, one important consideration before you recycle that old computer: Don’t forget to remove your personal data from the computer’s hard drive.
That may be easier said than done. To explain, I need to give you a little insight into how a computer deletes information. When something is erased from the hard disk, it is not really removed from the computer. You can press the delete key to remove a file. You can throw the file into the trashcan. You can even empty the trash. The file is really still there. Here’s the key bit of information you need to know. When you perform any of these actions to delete a file, the computer erases the address to the file, but it does not erase the file itself.
The computer has what is called a File Allocation Table (FAT). This table keeps track of all the addresses of every piece of information on the computer’s hard drive. When the computer is instructed to erase information, it simply removes the address for that information from the FAT table. To the computer, that address is now free, and the space on the hard drive that the address refers to may now be used to store new information.
When the computer user subsequently saves new information to the hard drive, the computer will look for a place to put the new information. It will check the FAT table to find available addresses. The computer now sees the previously used address as available, and it will write the new information over the information that was there previously. It is only after this overwriting occurs that the original information becomes inaccessible.
So, is there any way to actually remove all of the information from a hard drive? Well, reformatting the hard drive is often thought to erase the entire disk, but this is not true. The best bet is to completely erase a hard drive, reformat the drive and write zeros to the entire drive. This is sometimes referred to as a low-level format. Writing information, even if it is only a string of zeros, is the only way to completely overwrite any information that is on the disk.
While reformatting and overwriting the drive with zeros does effectively erase the entire disk for all practical purposes, specialized equipment can still sometimes detect a ghost or shadow images that may remains. While this is not a concern for most home computer users, some governmental agencies like the U. S. Department of Defense will overwrite the drive three times using 1’s, then 0’s, then 1’s again. For top secret information the DOD standards recommend that after the overwriting, the disk be demagnetized (degaussed), then physically destroyed by smashing it into pieces.
Understanding exactly how a computer erases data can be valuable to the average computer user. Have you ever erased a really important file? Now you know if you don’t write anything over that file, it may still be recoverable with a simple utility program. Have you ever wondered how to successfully erase your personal information from a computer before you give it away or recycle it? Now you know.
