Nature has shown us that information about the past can be retained for very long periods of time in fossils, ice cores and in magnetic particles in rocks that record the history of magnetic reversals of the earth’s poles, to name a few examples. In many of these cases the information is of a global or widespread situation—with many places where this information is stored. As a consequence of the non-local nature of this natural information storage, the destruction of many storage locations still leaves some records remaining. That is a good example of one important element in long term retention of information—multiple copies are needed in separate locationsto increae the odds of that information surviving for a longer time.
But keeping human information for the long term is more difficult to do. This is because there is so much more of it. This makes it hard to keep a lot of copies of this data in multiple places. Another issue is that our insatiable demand for more storage leads to denser storage technologies on media that has a finite life and also leads to our using data and hardware formats that may last for an even shorter time than the media. Are there things that people can do to extend the longevity of precious information? The answer is that there are efforts and products that may help us do this.
Regarding the longevity of storage media many of the products that we use today, hard disk drives, flash memory, optical discs and magnetic tape will react with the ambient environment and gradually lose the data stored on them or disintegrate over time. In either event the data stored on the media will not be accessible. Until recently the longest living storage media has been magnetic tape which may be kept as long at 30 years in the right environment with good odds that the data can be read back (assuming that the playback devices for that media still exist).
Recently a company from Utah called Millenniata has introduced an optical disc technology utilizing a disc in which the data is etched (or engraved) into a ceramic substrate rather than stamped on plastic like conventional optical discs. This ceramic substrate will not react with oxygen or moisture and is not damaged by temperatures that would significantly warp a conventional plastic optical disc. The company claims that if optical discs written with this process are stored in a location where they are kept from cracking or chipping the data can be read back years later—perhaps even 1,000 years later.
I have no doubt that this technology will do what it claims. A glass-ceramic substrate should be very stable and the only issue (or perhaps it is a benefit) over time is that the storage capacity of the disc remains fixed. Today’s 25 GB Blu-ray optical disc equivalent Millenniata disc may appear to be tiny and quaint in 100 years . However it has the potential of delivering information far into the future. The other big issue is whether the data can be read.
The SNIA Long Term Retention working group has been working hard to develop a Self-Contained Information Retrieval Format (SIRF). The SIRF standard provides a logical container for a set of digital preservation objects and a catalog of those objects. Digital preservation objects can be any sort of digital file or content. The catalog contains information (metadata) related to the entire contents of the container as well as to individual objects. SIRF standardizes the information in the catalog for the object containers. A valuable feature of this proto-standard is that objects that are related to each other are kept in a single logical container and SIRF compliant future applications would be able to read older content even if the original application program no longer existed.
A long term storage media such as the Millenniata ceramic disc and SIRF container storage (along with information on how to build a disc reader) could provide a way to transport useful information into the future. Of course creating more than one of these discs with the same information and putting those discs in different spots in the world will further increase the odds of data survival. Perhaps the means to effectively preserve information for the future is close at hand.
