Storing test data for the long-haul in digital form comes with risks. Should you keep paper copies for posterity?
In Preserving Data Books From Yesteryear, Aubrey Kagan told us how he painstakingly scanned data books and made the information searchable. That's great, as long as he has the hardware and software to read the files. If someone finds his designs 200 years on and wonders how they worked, will his digitized data books and schematics be of any help?
In 1998, I wrote an article for Test & Measurement World called "Arrange Test Benches More Efficiently" in which Kagan sent me a photo of how he used a computer monitor arm to hold an oscilloscope. You can read the PDF of the article in the link above because I still have my print copy to scan, as does Kagan. In fact, I have every print edition of T&MW from August 1992 through to the end in 2011. Those print copies could outlast all of the electronic versions that are now on EDN. In 200 years, someone will know how electronic products were tested, because reading them won’t require machine intervention.
Aubrey Kagan used this computer monitor arm to hold his oscilloscope in 1998.
Last week, I read an article in IEEE Spectrum about the movies and how they’ve been stored for the last century -- on film. The beauty of film is that it can last 100 years. All you need is a film projector. But, movies are going digital, at least in the short term. For the long term the article says that film is still the best option.
On Saturday, March 8, The Boston Globe posted an article about how people are giving up on safe-deposit boxes for storing documents and valuables. They're scanning documents and storing them in the cloud. Valuables such as jewelry are going in home safes. A local bank reported that safe-deposit boxes are in less demand. But the article noted that when a cloud service went out of business, the company gave just 24-hours notice for people to download their documents. Many were gone forever unless other copies remain.
These instances of storage made me think about how test and calibration data are stored. Granted, you probably don't need to keep test data for 100 years, but you may need a way to gain access to it many years after your company started (or stopped) producing a product.
The big problem with storing any kind of data for the long haul is "Will there be a machine that can read the data?" Systems and file formats change over time, and you may find yourself transferring data from an old format to another. I've done that more than once. For example, I once converted documents from Multimate to MS Word. Both formats use .doc file extensions, but they are incompatible.
If you have engineering or manufacturing records that are more than perhaps 10 years old, can you still read the data? If yes, then for how much longer? What about documents that were originally stored as hard copies? Do you scan them and upload them to the company network? If you destroyed the paper records, you'd better make sure that you'll be able to read them on some machine and have them stored in more than one place. Hard drives are disasters waiting to happen.
Therein is the beauty of hard-copy records. Remember, portions of the Dead Sea Scrolls survived in a cave for centuries. Once they were recovered, people were able to read them because the language had survived. They required no machine to see the words, though having digital images means we can see the artifacts from anywhere. Will the original scolls outlast their digital copies?
The Dead Sea Scrolls survived for centuries in a cave, and they just may outlive their digital images.
Of course, digitized test data is, at least in the near term, far more valuable than paper records. You can analyze digital data and discover things about designs and their manufacture that are impossible to achieve with paper copies. You can also easily keep copies of the data in more than one place in case of a disaster.
How long will it take for this iPad to become nothing more than a lighted serving tray?
—Martin Rowe, Senior Technical Editor