I Have External Hard drive with 320 GB. For now, I want to upgrade the capacity into 1 TB and Sell the Old 320 GB hard Drive. How can I delete all of my files safely, so the new owner of that hard drive cannot restore the data.
If you want to save your data from stolen or either you want that no body will recover your data from your hard drive then first of all permanent delete it by shift+del. After this process format all the partitions of your hard drive by Fat files system during the Windows process. Once you format its all partitions then your previous data will be deleted for forever and it will be safe for you because no body will be able to recover it from your hard drive. The following image of the inner side of the hard drive can clarify your concepts,
Dear Tamameddy,
There is one way how you can securely erase all the data from your external drive of 320 GB, so that it cannot be recovered or restored using any recovery soft wares. In order to do so, you have to Securely Erase your drive.
This can be done using some software, which can Securely Erase a disk in which the software over-writes every single on the hard drive. This even includes Bad Blocks, directories and everything else. When a drive is Securely Erased, no data can be recovered.
Some of the software's that can be used to do so are Eraser (which can be found on https://eraser.heidi.ie/) and Kill Disk (which can be found on http://www.killdisk.com/features.htm). These are free versions though so they might not work as well as the paid ones. I would recommend you to purchase Kill Disk of the site and then use that to Securely Erase the disk.
Hope this helped.
Standard DoD 5220.22-M / NISPOM 8-306
This is the solution. US Department of Defense in the clearing and sanitizing standard DoD 5220.22-M recommends the approach
"Overwrite all addressable locations with a character, its complement, then a random character and verify" (see table with comments) for clearing and sanitizing information on a writable media.
You can delete files permanently from your computer by using a file shredder software called Delete Files Permanently. Log on to www.deletefilespermanently.com to download this file shredder software.
