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Hard Disk Shredding


One of my holiday projects was to streamline my storage needs.  The recent floods in Thailand have affected global hard disks (HDD) supply.  The 3TB drive I bought four months ago for $129 goes for more than $300 now, and the shortage / high price period is likely to continue throughout 2012  as supply catches up with the shortfall. Hence the need to be even more careful than in normal times.

If you are building a new PC now, I strongly recommend a solid state drive (SDD) instead of an HDD for the system drive.  60GB SSDs sell nowadays below the current price for the lowest cost HDD of $100 and 60GB is more than sufficient capacity for the system drive of most users. Even the least of the SDDs outperforms HDDs by a magnitude of factors. Larger capacity HDDs are still critical for the storage of large quantity of data such as photo, audio and video, but this data need not be stored on the system drive.  I will try to stretch my existing storage capacity until the shortage is over and prices are back to normal.

HDDs have a limited life span.  The question is not whether an HDD will fail, but when.  The secret for data preservation has been known to the monks in the monasteries of Europe long before the introduction of Gutenberg’s press: replicate, replicate replicate.  RAID is an automated, modern incarnation of the monk’s painstaking manual process of replicating books to preserve their content in time.

While most HDDs come with a three years warranty, and some are even warranted for five years, the warranty is a false sense of security.  It does not cover the stored data and is only indicative of the expected useful lifetime of the device before data is lost due to a failure.  Most failures don’t result immediately in data loss, but the recovery becomes prohibitively expensive. On my desk I keep a 120 GB HDD that is more than ten years old and still working despite intense 24/7 usage during many years and a transatlantic move.  But I have also had HDDs that failed after less than a year.  If this happens in a RAID, it is not critical.

My strategy is to use only fresh HDDs for critical data; to store such data redundantly; and to replicate it to fresher / newer HDDs within a maximum of three years.  After their first job in the RAID is over, I re-purpose older HDD for non-critical purposes such as scratch or cache disks, but at some point they fail and the question is what to do with the waste. I bring old electronics to the municipal recycling station, but I take the HDDs out of them before doing so.  The abounding stories of sensitive data being retrieved from the HDDs of second hand PCs sold on eBays makes me reluctant.

Disassembling an HDD is not a difficult task. All you need are a couple of torx screwdrivers.  This was the occasion for a little bit of son-dad quality time.  My son was fascinated by using a real screwdriver rather than his toys.  He learned about magnetism from the two magnetic blocks of the drive’s actuator and he was fascinated by the mirror polish of the platters. Now all the parts can go to the recycling station, except the platters themselves which I will take care of rendering unreadable.

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