In his keynote address at the 11th European Conference on Digital Libraries in 2007 entitled “Digital Preservation, Archival Science and Methodological Foundations for Digital Libraries,” Seamus Ross analyzes the challenges confronting digital preservation, including technological obsolescence. He observes:
Digital objects break. Digital materials occur in a rich array of types and representations. They are bound to varying degrees to the specific application packages (or hardware) that were used to create or manage them. They are prone to corruption. They are easily misidentified. They are generally poorly described or annotated; they often have insufficient metadata attached to them to avoid their gradual susceptibility to syntactical and semantic glaucoma. Where they do have sufficient ancillary data, these data are frequently time constrained. Beyond maintaining the intactness of the bit stream (which is fairly straightforward), the long-term curation and preservation of digital materials is for the most part…a labor-intensive artisan or craft activity.
Cerf notes, “We digitize things because we think we will preserve them, but what we don’t understand is that unless we take other steps, those digital versions may not be any better, and may even be worse, than the artefacts that we digitized.”
Bit rot, in other words, can render our supposedly preserved information unreadable or unintelligible, thereby erasing ourselves and our history – our digital artefacts, happenings, and memories – from future generations.
[Cerf] explains that digital vellum would involve a process of taking “an X-ray snapshot of the content and the application and the operating system together, with a description of the machine that it runs on, and preserve that for long periods of time. And that digital snapshot will recreate the past, in the future.” This X-ray snapshot “should be transportable from one place to another. So I should be able to move it from the Google cloud to some other cloud, or move it into a machine I have.”
Cerf continues, “No matter what the medium is in which digital bits are recorded, how long will we be able to read them, and how long will we make sense out of them? So the issue here is not just the physical bits, but what do they mean. If you use a program, for example, to create a spreadsheet, you have a complex file. You store the file away and you hold onto it for twenty or thirty years. And even pretending you can read the disc again, do you have the software that knows what the bits mean? So the digital vellum idea is not just physical medium, but an ecosystem which is able to remember what bits mean over long periods of time.”
Marc Kosciejew, “Digital Vellum and Other Cures for Bit Rot,” The Information Management Journal 49, no. 3 (2015): 20-25.
