[Computer Corner]

Originally Posted by billethkid

I will soon be getting my new desk top. After I transfer all my files/programs to the new one, I would like to delete everything from the old one's hard drive. I have heard that a hard drive cannot be 100% cleaned.

Is this true? What do you recommend....other than drilling holes in the old hard drive.

btk

Before you go attempting to remove your data, and especially before you start 'drilling or soaking' a perfectly good hard drive, you need to understand how data works! There are perfectly safe ways to remove your data.. which I will explain at the end of this post. First you need to understand how computers handle the deletion of data.

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The following article was originally posted on our website, and can be found here: WARNING! DELETE DOESN'T ALWAYS MEAN DELETE!

DELETE doesn't always mean delete! (Part 1)
02/26/20120 Comments


We've all been there, the moment when you realize that you have deleted 'that very important file'. You know which file I'm talking about. It's the family pictures, or videos. Its the file you needed for your 'big project', or for 'the meeting'. It's the file that you worked hours on, meticulously slaving in front of your computer screen, spell checking, revising, grammar checking, revising, and so forth into the wee hours of the night. And then, in just one second with the wrong mouse click, you accidently deleted it and.. POOF! Its gone! Or is it?

" The truth is, when you delete something on your computer, it isn't really deleted."

The truth is, when you delete something on your computer, it isn't really deleted. When you press delete on your keyboard, or select delete from a menu, all you actually do is instruct the computer to remove the file from its File List, giving the computer permission to rewrite on that space, in the future. To understand how this works, think about your home. Deleting a file would be like removing the 'Mailing Address Numbers" from your mail box, and door way. By doing so, your house wouldn't cease to exist, but it would certainly be harder for the Pizza Delivery guy to find you! In the same way, when you delete a file from your computer, you are actually deleting the virtual address the computer uses to find that file. In other words, when you delete your file, the system doesn't "replace" or "Zero" the space, it simply frees it up to be reused at a later time. It is only when the file has been overwritten that it is actually deleted.

The reason your Operating System does this is to save time, and system resources. Just like your home, if you wanted to go 'off the grid', tearing it down would take a lot longer than simply removing the street address. Imagine trying to "overwrite" a large file that occupies lots of sectors on your hard drive. To really delete this file from your hard drive your computer would actually have to overwrite the data with new data. This could take a lot of time. Instead it simply removes the file name from the directory where the file is located and marks the sectors the file us as 'available space'. To reuse the house example we used earlier; Imagine if you put a sign in your front yard saying "FREE SPACE! BUILD WHERE YOU WANT". It may not take long for your house to be 'deleted' too! But, in the meantime... It's still there!

What does this mean for you?

Well, this could be really good news, or for some, really bad news! Why? Because, since your data wasn't really removed form the disk, it is possible to recover a deleted file. Even over long periods of time, and even after disks have been 'reformatted'! To do this Special Recovery software can be used to scan any storage device(like your hard-drive, thumb-drive, etc.) and search for these 'address-less' files. Once found, these files, as long as they have not been overwritten by new data, can be fully recovered, or in other words; a new address can be assigned to this property, taking the "FREE SPACE" sign out of the yard! Welcome back to the grid!

We saw an example of this during the famous "Casey Anthony Trial", where federal prosecutors where able to go back years into deleted history files to discover searches that were made from Casey's computer, like "chloroform".

This is welcomed news for those of you who need 'that file' for 'that meeting', but this also leads us to a very important security concerns if you have or have had very private, or confidential information on your computer, that you wouldn't others to find. Fortunately for you, there are also means of fixing this problem too! We will cover that in our next Blog "Delete Doesn't REALLY MEAN DELETE! Part 2"

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Now how to remove that unwanted data.. Here is a VERY BRIEF OVERVIEW:

1. Start by DELETING all the information that you don't want. (as I explained avove, this doesn't actually erase it, but it basically adds an extra layer of security, because eraser programs will search for deleted content to remove data from.
2. Reformat the drive. (and contrary to popular belief, Reformating does nothing do destroy data) Once again, this is just another step in prepping the drive to be officially erased.
3. Remove the drive from the machine in question. (If you are attempting to erase a drive that is in use, you will be locked out of a lot of important areas on the data structure.
4. Using another computer mount the drive, and use a program called Eraser. This program gives you an option between 1-32 passes, and is used by government agencies to properly wipe a drive.. I recommend at least 3 passes on your entire drive. Though technically one pass is more than enough..

I will be writing a new blog on this process at our website: Central Florida Geek- Computer Repair, Web-Design, Home Theater, iPhone repair, and More! - Technology Specialist, Affordable Computer Services Leesburg and Mt. Dora so stay tuned.