When it comes to IT, data security is paramount. No business wants to have its corporate files leaked to hackers, the press, or competitors. Home users are just as concerned, especially when they upgrade to a new computer and must decide what to do with the old one.
Deleting your data before you toss a hard drive isn’t quite enough.
Why Data Lingers
Hard drives work in a particular way. They divide the space on their disk into small chunks, each of them a specific size. When you write a file to your drive, a certain number of these sectors is taken up by the actual data, and the path to the file is written in the file table.
When you delete a file, all that takes place is the reference to the file is removed from the file table. This tells the computer that the sectors where that data is written are free to be used by other files. Sometimes the next file you write will overwrite those sectors.
Other times it may take months of constant use for half of the sectors to be overwritten. As hard drives get larger, the chances of those sectors being reused grow slimmer.
This means that, until the sectors are overwritten, the file is recoverable. This is good news for people suffering from hard drive crashes, but not as good for people who want their data gone. To truly delete the data, you need to write data over the sectors the data occupies.
IT Solutions for True Data Deletion
The process of overwriting ’empty’ space on a drive to erase lingering data is known as zeroing it out. This is because it involves a program writing data to the sectors, one or more times, with zeros. Keep in mind that all data on a hard drive is made up of binary code; in the form of zeros and ones. Another method, called the Gutmann method, involves writing the space over with a random sequence of ones and zeros that makes up random noise, not data.
Most of these technologies write over the data multiple times. Programs like Eraser use a Department of Defense standard with a three-pass and seven-pass mode, or use the Gutmann method calling for 35 passes.
The reason these programs write over empty sectors several times is because of the nature of hard drives themselves. Data on a hard drive is stored magnetically. Magnetic alignment of bits on a hard drive is impossible to completely erase. Traces of a file will linger even after the data has been overwritten. Only by overwriting multiple times can the original file be lost in the noise.
Freeraser is a utility that allows the user to delete a file and automatically have the sectors it occupies overwritten with data. Blank and Secure is a similar utility. Both of these programs immediately overwrite the data, which extends and delays the deletion process.
What about files you’ve already deleted? You can’t call them back from the grave to delete with Freeraser, but the data may still exist. Utilities like DP Shredder are what you need in this instance. DP Shredder has an option to overwrite all of the free space on your hard drive with either zeros or random binary noise.
Finally, CCleaner is the ideal utility for a scorched earth deletion. It has an option for one-, three-, seven- and thirty-five-pass deletion schemes that wipe your entire hard drive. While it’s not useful to computers in use, a multi-pass overwrite is ideal for scrubbing a hard drive of data before it is sold or thrown away. Not even a reformat is that secure.
Author Bio: David Malmborg works with Dell. When he isn’t working he enjoys hiking, spending time with family and researching about new technology. He is currently learning more about IT Solutions and recommends following this link for more information.