One of the more frequent arguments we hear against shredding hard drives, is that the hard drive can not be used again. This is certainly true – but we ask the question “why would you want to”. So we sat down and ran some numbers.

For the sake of our experiment, lets say we want to destroy the information on one hundred 100 GB hard drives.

Option 1 is to do a “DoD wipe” on them. DoD 5220.22-M says you should “overwrite all addressable locations with a character, it’s compliment, then a random character and verify”. The Gutmann method calls for a 35 pass write! Others say 7 times is the best.

You can do some calculations for yourself, but to write 100GB to a drive 3 times, means you would write 300GB of data, or 35 times, 3.5TB of data. That is going to take some time. Lets assume for our argument that this is going to take the better part of a day. Let’s also assume that you have built a setup that can do 5 drives at a time. We are still looking at 20 days to get the drives all erased. Assume further that your $40k a year data wipe technician spends three hours a day, or 60 hours setting up, checking and running the wipe – you have spent at least $1,200 and 20 days to get these drives wiped. At this point, you have 100 used drives (the mean time between failure – MTBF – does not change) that have no visible external characteristic that can verify that the information has been removed from the drive. There is a risk that in 20 days of the drives laying around, one could get lost, stolen or overlooked. And sooner or later one or more of those drives is going to fail, and at that point you can’t write data to it -so it has to be physically destroyed.

On the other hand, 100 hard drives can be shredded for about $500-$700. Buying new replacement drives in bulk should run you around $1,500 – so you are looking at about $2,200 and about 2 hours of a tech’s time to remove the drives, have ShredDisk come out and scan the serial number, shred the drive and give you a certificate of destruction listing the serial numbers of the drives. Also, just by looking at the shredded drives, you can tell that no data is going to be gleaned from these drives. Oh, and the shredded material is sent to a certified recycler, AND you get brand new (possibly larger and faster) hard drives in your computer, with a reset MTBF. This is assuming that the computers needed new drives, and you were not just decommissioning the off lease or end of life computers. That being the case, the cost is just the cost of shredding the drives.

At the end of the day, only physical destruction of the hard drive gives you visible proof that information that was stored on a hard drive was destroyed. Hard drive destruction using ShredDisk’s mobile hard drive shredding trucks provides tangible proof against data breach.