CDs and DVDs longevity questioned

DVD-R read/write side (from
DVD-R read/write side (from

In a recent article from BBC on Should you store treasured data on (optical) disk the conclusion was that CDs and DVDs have significantly worse archive life than advertised or even suspected until recently.  The study done by the French National Centre for Scientific Research discovered that the reliability of a few optical disks was just over one year and most “rarely lasted longer than five to 10 years” although they were advertised to last significantly more.

There was not much detail in the BBC article and searching (in English) for the original research yielded nothing pertaining to the topic.   However, the article did say that the centre used accelerated life testing with heat, water vapor and light (standard IT industry practice) to determine point of failure and that products under the same brand had significant archive life variability due to multiple manufacturers.  They also stated that branding the discs might be impacting longevity as well. And that it appeared that the more than seven miles of (probably DVD) data recorded on the discs is deteriating faster than anticipated.

As a result, they suggested that data on optical disks should be copied every two to three years and maybe as time moves on, this can be done less frequently assuming optical disk lifespans improve.  Also important data should be spread across multiple storage formats.

The case for (IT) tape in video archives

Nonetheless, the article did mention that a 52 minute documentary typically requires about 500GB of high definition video to be recorded and at the moment that video is normally stored on data (tape) cassettes and hard drives.  In my experience these (video) tapes were specific to the recording equipment vendor, i.e. Panasonic, Sony, or others and as such, relatively expensive.  But nowadays, this data can also be stored on LTO or other IT tapes.  In contrast to the above, LTO tape has an archival storage life of around 30 years (depending on vendor) and can be had at reasonable cost.

Also, in the past I was aware of a number of TV broadcasters that had an archive of finished broadcasts residing only on DVDs.  They typically took one additional copy of a DVD and stored them both in their desks or file cabinets.  Many of these people will be very surprised when five years down the line, they go to access their archived broadcasts and find that they can no longer be read.  Of course, I have made the same mistake with my family video archive stored on DVDs.

Video archives whether of raw video or finished broadcasts require large capacity, sequentially accessed storage which seems ideal for automated LTO or other magnetic tape storage.  By using IT tape data storage for video archives, one can benefit from technology advances in density and throughput that happen every couple of years, benefit from volume manufacturing available to IT product manufacturers, and benefit from a significantly longer archive life.

Now if I can just find a USB LTO tape drive that works on the Mac for my home videos and family backups I would feel much better, …

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