It is also worth noting what other commentators have decided to be the require- ments for effective digital preservation strategies and practices. One way of doing this is to analyze responses to the threats to digital preservation.
Respondents to a survey of RLG members in 1999 ranked the threats, in order of significance, as ‘technology obsolescence, insufficient resources, insufficient planning; and physical condition of materials’ (Hedstrom and Montgomery, 1999, p.19). This suggests that effective approaches to and strategies for digital preservation need to address these concerns, so our list of criteria could include the requirements that the approach or strategy should be independent of tech- nology, that it must be adequately resourced, that it is planned in detail, and that attention is paid to improving the physical condition of media.
Jeff Rothenberg has commented extensively on some of the requirements. He encourages ‘a sound technical approach’ as the basis of any approach, recog- nizing that there are many inter-related issues that must also be addressed, such as ‘technical, administrative, procedural, organizational, and policy issues’
(Rothenberg, 1999b, p.6). He elaborates that ‘any technical solution must be also able to cope with issues of corruption of information, privacy, authentication, validation, and preserving intellectual property rights’ and ‘must be feasible in terms of the societal and institutional responsibilities and the costs required to implement it’ (Rothenberg, 1999b, p.9). His ‘ideal approach’ would be a single solution that is long-lived and can be ‘applied uniformly, automatically, and in synchrony (for example, at every future refresh cycle) to all types of documents and all media, with minimal human intervention’ (Rothenberg, 1999b, p.16):
The long-term digital preservation problem calls for a long-lived solu- tion that does not require continual heroic effort or repeated invention of new approaches . . . This approach must be extensible, since we cannot predict future changes, and it must not require labor-intensive transla- tion or examination of individual documents. It must handle current and future documents of unknown type in a uniform way, while being capable of evolving as necessary. Furthermore, it should allow flexible choices and tradeoffs among priorities such as access, fidelity, and ease of document management (Rothenberg, 1999b, p.30).
This is a tall order. Implicit in Rothenberg’s comments is the idea that there is a single technical solution – he is well-known as championing emulation as this single solution; but others do not agree. More recently, Lavoie and Dempsey have suggested that factors such as ‘cost, user preferences, nature of the material, 1111
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Criteria for effective strategies and practices 107
whether it exists in multiple forms’ need to be taken into account when ascer- taining which preservation strategies are appropriate (Lavoie and Dempsey, 2004).
Thibodeau has identified four criteria by which to ascertain the best strategy:
• its feasibility (is there software and/or hardware capable of doing it?),
• its sustainability (can it be done into the future, or can an alternative future path can be identified?),
• its practicality (can it be applied within reasonable limits of difficulty and expense?), and
• its appropriateness (this criterion relating to the type of objects and why we are preserving them) (Thibodeau, 2002, pp.15–16).
To illustrate these he describes a spectrum of possibilities, ranging from
‘preserving technology itself to preserving objects that were produced using information technology (IT)’ (see Figure 6.3). The suitability of any strategy and practice, which Thibodeau calls ‘methods’, can be determined only with respect to the nature of the material being preserved. Computer games, for example, are much more likely to require methods that fall at the ‘preserve technology’
end of this spectrum, whereas e-mails fall at the ‘preserve object’ end. Some methods are general and some apply only to specific technologies, for example specific software and/or hardware, or specific data types. Therefore, the
‘range of applicability is another basis for evaluating preservation methods’
(Thibodeau, 2002, p.17).
Nor must we forget the requirements for authenticity, noted in Chapter 5, in digital preservation. Because ‘an authentic digital object is one whose genuine- ness can be assumed on the basis of one or more of the following: mode, form, state of transmission, and manner of preservation and custody’ (Ross, 2002, p.7), it follows that effective digital preservation strategies and technologies must ensure that these requirements are not forgotten. We should keep in mind Gilliland-Swetland’s cautionary comments:
Counterintuitively, perhaps, it is during the preservation of digital mate- rials that evidential value is often most at risk of being compromised.
Digital preservation techniques have moved beyond a concern for the longevity of digital media to a concern for the preservation of the information stored in those media during recurrent migration to new software and hardware. In the process, many of the intrinsic character- istics of information objects can disappear – data structures can be modified and presentation of the object on a computer screen can be altered (Gilliland-Swetland, 2000, pp.11–12).
ERPANET has produced a guide to assist with selecting digital preservation technologies in its erpaTool series (ERPANET, 2003). They provide a list of eval- uation factors, reproduced here, with minor amendments, as Figure 6.2.
Finally, we need to note the effect of national information infrastructures on approaches and strategies for digital preservation. Effective approaches and strategies will work best if supported within these infrastructures. Also relevant here are the possibilities for cooperation: for example, Beagrie’s 2002 survey of national digital preservation activities indicated that ‘national libraries offered
108 Overview of Digital Preservation Strategies
FactorsRemarks GeneralMaturityIs the technology fully developed and are there already systems in productive use? ExperienceAre there already verifiable experiences in applying the technology for the preservation of similar objects? SpreadIs the technology widespread enough to guarantee that it will be supported by the manufacturers during the desired lifespan of the preservation system? Standardization;Is the technology based on standards and are the specifications of all the critical elements laid open by the open specificationsmanufacturers or at least deposited with an independent and trusted third party and available there in case of the dissolution or downfall of the manufacturers? ReliabilityDoes the technology work reliably and can the reliability of the outcome easily be checked? Modularity and Is it easily possible to add new components at low cost, to change or update them? flexibility CostsIt is important to include not only the price of system components, but all cost of implementing and maintaining the system. See for this purpose the erpaToolon cost orientation. ObjectsLegislationAre the objects subject to specific legislation which asks for a specific form, format, storage medium, or accessibility? Such regulations are basic conditions for the selection of technologies. CharacteristicsHow can the main characteristics of the objects and their context be preserved without threatening authenticity and integrity? As conversion of digital objects for preservation is often difficult and costly, all selected technologies must be able to treat current and, as far as possible, also future objects. Consider also carefully what consequences a selected technology has regarding the creation or preparation of the objects for preservation. Preservation periodAs digital systems only have a life span of about five to 10 years at highest and digital objects must be preserved for much longer periods, it is important that the system is able to efficiently export objects and their context data in standard formats in order to migrate them into a new system. PeopleSkillsDoes the selected technology need specific skills which must be available in-house? Are these skills already available or can they easily be acquired? Staff for maintenanceIs the appropriately skilled work force in the right number for the maintenance available? ExperienceIs there sufficient experience with the technology for support in case of difficulties available? (in-house or easily accessible in the region) ProceduresWorkflowCan the technology easily be implemented in the preservation workflow or can the workflow be adapted to the technology without major difficulties or loss of efficiency? FlexibilityCan the technology flexibly be implemented? Does it allow changes in the preservation procedures? Good practicesAre good practices in using the technology already established? Quality requirementsCan the technology meet the previously defined quality standards? However, automatic or semi-automatic techniques are difficult to be applied for heterogeneous collections, complex objects, and high quality requirements. Figure 6.2Factors to Consider when Selecting Digital Preservation Technologies (Modified from ERPANET, 2003, pp.4–5)
several recurring suggestions for international cooperation in developing effec- tive strategies for long-term preservation’ (Beagrie, 2003, p.6), and the example of a preservation technology watch was offered.