Technology is required for the digital preservation program at many levels to:
- create digital content
- capture content and associated metadata as digital objects
- transfer those objects to and within a digital repository
- process or otherwise interact with digital objects in the repository
- find and deliver stored objects
- build and maintain the repository
- define and implement the policies and protocols that pertain to the repository
- integrate the repository and the digital materials into the broader organizational environment and the contexts in which it operates
Preservation planning is more than just recommending and adopting preservation strategies, which in itself is hard enough. The development of a technological infrastructure to sustain the digital preservation program requires a holistic design and implementation that will respond to evolving requirements. The OAIS standard defines these functions for preservation planning:
- Monitor Designated Community (referring in this case to producers and consumers—see the Foundations Documents discussion of OAIS roles) to track changes in requirements and mechanisms.
- Monitor Technology to embrace enabling technologies and to avoid the potential for obsolescence and incompatibility.
- Develop Preservation Strategies and Standards
- Develop Packaging Designs and Migration Plans to develop plans and prototypes for implementing recommended digital preservation strategies and for implementing preservation policies and directives.
A technological platform must be assembled, scaled appropriately, documented, monitored for key developments, and upgraded or enhanced as necessary. Most organizations that already have digital content to manage are familiar with the twin pillars of systems support: file management and storage management. Doing these two functions is an important starting point. But beyond that, organizational decisions about technology—hardware, software, networks, staffing—can either enable or deter a digital preservation program. For example, the list below includes examples of technologies that may be required to make digital objects both renderable and understandable:
- basic data encoding (e.g. EBCDIC, ASCII, Unicode, big-endian, little-endian, word size)
- file formatting and compression schemes (e.g. Microsoft Word 97, AutoCad 10, JPEG, TIFF, JBIG, LZW)
- storage media specifications (e.g. 3.5" floppy diskette, 12 cm optical disk)
- media storage techniques (e.g. magnetic, optical, magneto-optical)
- storage media formatting (e.g. CD-Audio Red Book, CD-ROM Yellow Book, Orange Book CD-R and CD-RW)
- file system specifications (e.g. FAT32, ISO-9660, HFS+)
- operating system environment (BIOS ROMs, system calls, linked libraries)
- storage hardware, with associated firmware, device drivers
- "playback" hardware (e.g. audio/video subsystems and displays and printers)
Every one of these components must interact and recognize the others in order to achieve long-term maintenance of a bitstream and continued accessibility of its contents. Given the rapid pace of technology change, each of these technologies is subject to obsolescence. Managing the availability and interaction of these technologies to support digital preservation is a constant challenge.
There are four possible scenarios for developing the technical infrastructure. Each has its strengths but the right solution will depend upon your institutional capabilities and priorities. The four options are:
- Opt to build on internal IT for DP program.
- Focus on developing capacity and storage options.
- Define based upon gap analysis.
- Add capacity and storage.
- Ensure adequate redundancy in backup.
- Evaluate alternatives then outsource or subscribe to service.
- Ensure longevity through effective contract/service management.
- Specialize in core areas of expertise or capacity.
- Extend capacity through collaboration.
- Share well-defined responsibilities.
- Leverage extra-repository benefits.
Which is right for you? Consider the following characteristics:
|Do you have existing digital content?||No||Yes||Yes||Some|
|Do you have access to or control over IT infrastructure?||Yes||Yes||Minimal||Maybe|
|Do you have a repository to leverage?||No||Yes||No||Maybe|
|Do you have startup resources?||Yes||Baseline||Limited||Limited|
|Do you have sustaining resources?||Yes||Limited||Limited||Limited|
Digital Preservation Strategies
Many digital preservation strategies have been proposed, but no one strategy is appropriate for all data types, situations, or institutions. See Section 2, Terminology: Strategies for a brief tour of the range of current options. Some clearly address only a subset of the technical concerns, while others would be widely applicable. Some are in use today; some remain largely untested, especially in cultural institutions. Others represent theoretical possibilities that research groups are currently exploring.
How does one know when changes in hardware and software will put a digital collection at risk? The answer: by actively monitoring technology developments and systematically considering potential preservation implications. Currently there is no central place where all of the necessary information has been brought together. Such a registry—if it existed—would have information about all the versions of every software package and piece of hardware in use, as well as literature and other indicators from domains of all kinds that refer to, contemplate, or otherwise discuss recent, current, and future developments. It would contain compatibility information—the interrelationships among file formats, software, and hardware versions. In an ideal world, this information would be an automated system with a risk monitoring module that would send alerts when a collection was put at risk by a coming change in technology. In the meantime, individual and collaborative efforts to stay informed are essential, including reading technology news, talking with vendors, and communicating with colleagues. Subscribe to padiform-l, the National Library of Australia’s list for digital preservation. Another source is the IFLA DIGLIB list, an active list about digital library information, with some traffic about digital preservation and technology. Read RLG DigiNews (back issues) and D-Lib Magazine, among others.