If you’re like me, you’ve approached the idea of buying movies on a digital service with apprehension. Can you really own something that you keep no copy of? Though, if you’re like me, you also have DVDs of movies that you’ll likely never watch again. And a few VHS tapes you can’t quite throw out, despite no longer owning a VCR (I’m sure I can get one off eBay if I need it). And maybe some cassettes. If you think about it, we’ve really gone through a lot of mediums in the last few decades. It presents an interesting challenge to those who wish to store things for an extended amount of time: How do we store those files?
Phase 1: Magnets!
It’s very likely if you owned a computer in the 80s or 90s, you had some sort of floppy drive, and probably several floppy disks. These use a special film that contains magnetic film that can be written on and read with a magnetic head of a floppy drive. Hard drives are a larger version of these, with more robust film that is self-contained. Both of these mediums have an entropy problem though. Over time, the various little tiny magnetic fields all over the drive interact with one another as well as the Earth’s magnetic field and slowly all move towards becoming the same. The current estimates for magnetic tapes, floppy drives, and hard drives are 10-20 years, so if it’s recorded before the Millennium, it’s probably not very good.
It is possible, using a tool that reads and rewrites all data on a drive, to refresh it and keep it in good condition. This has to happen before the data is too far gone. Ultimately, it’s not the sort of thing you want to use to keep your cherished files in a drawer.
Phase 2: Lasers!
In the early 2000s came the era of burnable CDs, DVDs, and later Blu-Ray. These offered much more storage capacity as they used a laser to burn holes in a film on top of a plastic disk, which could be made more finely than the magnetic cells of other mediums. That’s right, it’s not the plastic, it’s the shiny part! However, these disks degrade over time, with the film on top lasting roughly 5 years. Commercial DVDs are made with a much more robust and expensive film, and are predicted to last 50 years, so no worries about needing to purchase another copy of 3 Ninjas: High Noon at Mega Mountain just yet. Verbatim sells a burnable DVD and Blu-Ray medium called M-Disc that they claim lasts 1000 years, but I’d not bank on that. If you have precious photos of your children on a CD, you might want to move it to another medium.
Phase 3: Transistors!
Flash drives and SSDs are the future and they are here! These use tiny transistors separated by an insulator to store electric charges. These charges can be sensed remotely without much work, which mean that flash drives are able to be read nearly an infinite amount of times. To write to them, the voltage must be increased enough to pass through the insulation and leave some charge behind. This breaks down the insulation, leading to a limited number of writes (though still tens to hundreds of thousands of times). But the longevity problem is similar to magnetic mediums: entropy. Over time that charge slowly drains out, as no insulator is perfect. If you were to read and rewrite the bits on a flash drive, you would refresh it, but otherwise you’ll only get 5-10 years out of it sitting on a shelf.
Phase 4: Rock!
Scientists have been looking into weird, stable materials to make true long-term storage available. This has led to the current long term winner: Quartz. This rock is very abundant, can be melted into the desired shapes (currently about the size of a US Quarter), and are very chemically stable. These discs are written to with lasers, which encode data in 5 dimensions (X, Y, Z, angle light hits it, and the colors of light that are refracted back). A single coin can hold an estimated 350 TB of data for millions or billions of years without degrading. Currently, no company has attempted production (though Hitachi has tried a similar Quartz based medium closer to a normal CD but never made it to production).
Conclusion: Ever Forward
It’ll likely be several years or more before truly long-lasting storage becomes available to the public. Until then, the best bet for consumers adverse to the Cloud will be to keep their precious files preserved is the unfortunate task of moving all of your files to the newest, cheapest medium for now and to check every year or two that things are still in order.