How to safely dispose of your old computer and hard drive

It is not enough to merely delete files or format your drive. You must do a SECURE ERASE or destroy the platters with a hammer!

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Over time, our computers and other electronic devices accumulate an astonishing amount of information that, if it falls into the wrong hands, can have extremely negative consequences on our personal and business lives. It is therefore essential that you take steps to prevent the loss of data in the event a computer, hard drive or cell phone is lost or stolen. As we have discussed here in other posts one of the best ways to protect your data is to encrypt all of your hard drives and other storage media using a high quality encryption algorithm (i.e. 256 bit AES). If you have not yet implemented disk encryption on your computer I strongly suggest that you take time now to get up to speed on this critically important security measure.

Now that we’ve got the service message out-of-the-way, I’m going to move on to discuss what you need to do when it’s time to dispose of or donate your old hardware.

The first thing to realize is that if your machine is not using full disk encryption, your data is wide open and easily read by anyone who has physical access to the machine or hard disk. Therefore, if you donate the machine to the local thrift store or charity or otherwise just throw it in the dumpster there is no telling who can eventually get their hands on your data!  Be assured that there are people who make a living by visiting thrift shops and land fills looking for old hard drives that they can mine for data or simply sell to others who will do the tech work of pulling the information from the disks.

So, how exactly do you remove your data before donating or disposing of your machine? You might think that simply deleting files or reformatting the disk would be sufficient but you’d be wrong!

Deleting a file merely removes the references to the locations to the data from the file system. The data remains on the disk until another program happens to write over the area of the disk where the file resides. With a big disk that could be a long time! In fact, deleted files are often easily recoverable either in whole or in part months and years after they have been deleted!

Formatting a disk might seem like a better option but again it does not guarantee that your data cannot be read by someone with skill and the determination to do so. If you look into the subject deep enough you will discover that it’s actually quite difficult to remove all traces of information from a mechanical hard drive. The problem is this: Even though the hard drive is a precision mechanical device, it is not perfect so there are always small errors in placing the mechanical read/write head a specific locations on the disk surface. This combined with the spreading effect of magnetic fields means that some information always gets written into the “empty” spaces between tracks and cylinders. It is therefore possible for skilled and determined individuals to read old data on drives even after it has been completely rewritten with new data!

There basically two approaches to making sure the data is inaccessible depending on whether you are disposing of or recycling the drive.

Hard Drive Disposal

If you are disposing of the drive you can take the following steps to make sure that the data on the drive is unreadable.

  1. Remove the drive from the computer or its external housing.
  2. Use a screw driver to remove the screws from the cover.
  3. Put on safety glasses and some heavy work gloves.
  4. Carefully use a hammer to smash the platters into little pieces.
  5. Dispose of the remains according to your local codes.

Hard Drive Reuse / Donation

If you intend to donate the hardware, including the hard drives to a school, charity or friend, you can use software tools to write multiple passes of random data to all locations on the hard drive platters. This can be a very time-consuming process (think many hours to perhaps several days for a large drive), but it makes it extremely unlikely that anyone can retrieve your data from the drive. There are two ways to go about wiping the drive with software depending on whether or not the old drive can be temporarily connected to another computer. The approaches are outlined below.

Drive Can Be Installed in Another Computer

If you have another computer that can accept the old drive either internally or via externally via a USB / Firewire / eSATA connection then you can simply boot your normal OS and run utilities to wipe the old drive. If you find yourself doing a lot of maintenance work with hard drives, I can highly recommend the Vantec CB-ISATAU2 SATA/IDE to USB 2.0 Adapter since it makes it easy to connect  both notebook and desktop type drives to the USB port on your computer. Once you’ve got the drive connected you can then use any one of a number of programs to wipe the drive depending on your OS. Just be extremely careful to make sure you’re wiping the old drive and not the other drives connected to the system! Here are a few recommended wipe utilities:

Drive Can NOT Be Installed in Another Computer

If you can’t install the old drive in another computer due to due to limited space, drive type incompatibility, etc., you  can wipe the drive while it’s connected to the old computer. Assuming that the hardware is working you will need to boot another OS or utility long enough to wipe the drive. Here are a couple of outstanding free utilities:

  • Darik’s Boot and Nuke is an excellent tool that automatically and irrevocably wipes all detected hard drives. Use it with care!
  • Parted Magic has secure SATA erase and Linux wipe functions along with extensive partition management tools. You’ll really like this one!

Both of the above options will likely work common PC hardware. They may even work on modern Mac’s as well but I have no way of verifying that.

Well that should be enough to get you safely disposing of your old hardware without giving away any information on you, your family or your business!

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2 comments

  1. build a computer, desktop gadgets, top gadgets, buying a computer, newest technology, build your own laptop, parts of computer

    I stumbled on this blog a couple weeks ago and I absolutely cannot get enough! Please keep writing!

  2. Security Alert! The TrueCrypt Debacle - Security Beacon

    […] If you are one of the millions of users still using Windows XP, then it’s time to completely jump ship and fast! Yes, TrueCrypt was the best friend Windows XP users ever had, but there is now a cloud over both systems. I don’t care whether you buy a new PC or Mac, upgrade to Windows 7 or 8, or make a dive into Linux. The time to do something is now! Just make sure to use whatever disk encryption system is available on your new setup, and properly deal with the remaining data on the old PC. In other words, don’t just shuffle it off to the thrift shop or the trash without securely wiping or completely destroying the drives! […]