Only way to really trash data is to destroy the hard drive
There are many reasons for wanting to delete data off of your computer's hard drive.
But sometimes, you haven't really gotten rid of it. Recent news stories, for example, have described how local executives got into hot water when data they thought was gone was, in fact, still there.
So whether you're donating your PC to charity or surreptitiously deleting porn or confidential financial information, there are a few steps you should follow to make sure the data on your hard drive is really unrecoverable.
Can't I just drag the files to the trashcan and empty it?
Well, no. The crux of the problem is that deleting files in this manner doesn't really erase the information. What gets deleted is the information that tells your operating system where to find the file. This is akin to deleting the table of contents from a book; the information is still there, but the reader can't find it. Unfortunately, any geek worth his weight in dilithium can easily find and read these files.
We recommend using a tool that actually deletes the information contained in your files. Towards that end, we've been using Darik's Boot and Nuke (http://dban.sourceforge.net) for Windows and Linux based computers. DBAN is licensed as open-source software under the General Public License. This basically means that, a few twists and turns aside, it is free to use.
There is also a commercial version of DBAN that provides additional features for enterprise use.
Once downloaded, DBAN can be easily installed onto a floppy, CD, DVD, or USB drive. Boot up your box from your DBAN install, and you are good to go. DBAN employs several methods to clean your drive, any of which are good enough for the average Joe.
For Macintosh users, Apple provides its own tool for wiping out a drive. Check out this URL for step-by-step information: http://docs.info.apple.com/ article.html?artnum=107437
Honestly, however, none of these processes are absolutely foolproof. If you really want to ensure that no one sees your data, you need to physically destroy the disk. We've heard of folks who use heavy duty drills to put holes all the way through the drive casing, or even using heavy-duty construction equipment such as backhoes or bulldozers to shatter the metal. In any case, it will take some serious elbow grease to destroy your drive such that all the data is gone. Clearly, this will render the hard drive unusable, so charities may not like this approach.
is president of ISDI Technologies Inc., a Honolulu-based IT consultancy. Call him at 944-8742 or e-mail firstname.lastname@example.org