The world’s first hard disk was invented in 1956. It weighed 450 kilograms and stored five megabytes. It was obsolete within five years. Those 8-inch floppy disks from the 1970s are unreadable. Data stored on Syquest, Zip, MO, and Bernoulli disks are also unreadable unless you have saved the drive and have a computer with a SCSI connector. I have Firewire backup drives that are unusable on some Apple computers: there is no Firewire plug.
Data rot is the tendency of our recorded media and computer files to become inaccessible as they are orphaned by new technology. Over time, temperature, humidity, light and mouldy basements make this information very difficult to read.
Another aspect of data rot is finding machines to read old media. Take the 8-track tape player, for example. The only way you can find 8-track cartridges is in a flea market or a garage sale.
The same is true of file formats. We can’t open Microsoft Word documents from the early days, because today’s Word can’t open those early files. Apple has eliminated optical media from some its computers. Try to find a reader for an 8-inch Shugart floppy disk. We are about to enter a new era of data rot, as consumer videotape fades away. CD-ROMs are also going fast, replaced by DVDs and USB thumb drives.
VHS tapes can still be played even if there is an error on the tapes. With a CD or a DVD, if there’s an error, the disk is non-recoverable. Many of us are paying to have old audio and video recordings transferred to CD and DVD. CDs are almost gone. The lifespan of DVDs varies from five to 100 years, according to testing but that assumes that there are drives to handle them. There may not be.
If you leave data on your hard disk, the drive only lasts five years or so. So every five or 10 years, we must move our files onto a different format. We must make back-ups in different formats, stored in different places. Keeping it on the web is also not a really great strategy. A very large photo site just went out of business.
Yet, a major trend is the “cloud”. This means you are using someone else’s disk drives. They are not in the sky, they are somewhere on earth in a server farm. Will those files be there 20 years from now?
Thomas Edison invented the Dictaphone that used a wax cylinder to record your voice. To erase it, you treated it like a lathe; you would use a sharp metal rod and scrape off the wax until it was smooth again, and then you could re-use it. But if you saved it you could play it until the needle wore the wax down.
A technology for long-term data preservation was developed at Lawrence Livermore National Laboratory: a titanium disk the size of a long-playing record that was supposed to last 10,000 years. Then they realised there were assumptions that weren’t right, and it would only last 20 years.
Even though most US government publications are electronic, many are printed in short runs to be stored at Depository Libraries and the National Archives. Why? Because the only data storage medium that has proven to be readable after 200 years is – paper!
Frank Romano is professor emeritus at the Rochester Institute of Technology
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