Illustration by Jørgen Stamp digitalbevaring.dk CC BY 2.5 Denmark
Introduction
The use and development of reliable standards has long been a cornerstone of the information industry. They facilitate the access, discovery and sharing of digital resources, as well as their long-term preservation. There are both generic standards applicable to all sectors that can support digital preservation, and industry-specific standards that may need to be adhered to. Using standards that are relevant to the digital institutional environment helps with organisational compliance and interoperability between diverse systems within and beyond the sector. Adherence to standards also enables organisations to be audited and certified.
Operational standards
There are a number of standards which can help with the development of an operational model for digital preservation.
Taking custodial control of digital materials requires a set of procedures to govern their transfer into a digital preservation environment. This can include identifying and quantifying the materials to be transferred, assessing the costs of preserving them and identifying the requirements for future authentication and confidentiality. ISO 20652: Space Data and Information Transfer Systems - Producer-Archive Interface - Methodology Abstract Standard (ISO, 2006) is an international standard that provides a methodological framework for developing procedures for the formal transfer of digital materials from the creator into the digital preservation environment. Objectives, actions and the expected results are identified for four phases - initial negotiations with the creator (Preliminary Phase), defining requirements (Formal Definition Phase), the transfer of digital materials to the digital preservation environment (Transfer Phase) and ensuring the digital materials and their accompanying metadata conform to what was agreed (Validation Phase).
ISO 14721:2012 Space Data and Information Transfer Systems - Open Archival Information System - Reference Model (OAIS) (ISO, 2012b) provides a systematic framework for understanding and implementing the archival concepts needed for long-term digital information preservation and access, and for describing and comparing architectures and operations of existing and future archives. It describes roles, processes and methods for long-term preservation. Developed by the Consultative Committee for Space Data Systems (CCSDS) OAIS was first published in 1999 and has had an influence upon many digital preservation developments since the early 2000s. A useful introductory guide to the standard is available as a DPC Technology Watch Report (Lavoie, 2014).
An OAIS is ‘an archive, consisting of an organization of people and systems that has accepted the responsibility to preserve information and make it available for a defined ‘Designated Community’. An ‘OAIS archive’ could be distinguished from other uses of the term ‘archive’ by the way that it accepts and responds to a series of specific responsibilities. OAIS defines these responsibilities as:
- Negotiate for and accept appropriate information from information producers;
- Obtain sufficient control of the information in order to meet long-term preservation objectives;
- Determine the scope of the archive’s user community;
- Ensure that the preserved information is independently understandable to the user community, in the sense that the information can be understood by users without the assistance of the information producer;
- Follow documented policies and procedures to ensure the information is preserved against all reasonable contingencies, and that there are no ad hoc deletions.
- Make the preserved information available to the user community, and enable dissemination of authenticated copies of the preserved information in its original form, or in a form traceable to the original. (Lavoie, 2014)
OAIS also defines the information model that needs to be adopted. This includes not only the digital material but also any metadata used to describe or manage the material and any other supporting information called Representation Information.
The OAIS functional model is widely used to establish workflows and technical implementations. It defines a broad range of digital preservation functions including ingest, access, archival storage, preservation planning, data management and administration. These provide a common set of concepts and definitions that can assist discussion across sectors and professional groups and facilitate the specification of archives and digital preservation systems.
OAIS provides a high level framework and a useful shared language for digital preservation but for many years the concept of ‘OAIS conformance/compliance’ remained hard to pin down. Though the term was frequently used in the years immediately following the publication of the standard, it relied on the ability to measure up to just six mandatory but high level responsibilities. A more detailed discussion about ‘OAIS compliance’ can be found in the Technology Watch Report.
ISO/TR 18492:2005 Long-term preservation of electronic document-based information (ISO/TR, 2005) provides a practical methodology for the continued preservation and retrieval of authentic electronic document-based information, which includes technology-neutral guidance on media renewal, migration, quality, security and environmental control. The guidance is developed to ensure authenticity of records beyond the lifetime of original information keeping systems.
ISO 15489:2001 Information and documentation -- Records management (ISO, 2001) can also be a useful standard for defining the roles, processes and methods for a digital preservation implementation where the focus is the long-term management of records. This standard outlines a framework of best practice for managing business records to ensure that they are curated and documented throughout their lifecycle while remaining authoritative and accessible.
ISO 16175:2011 Principles and functional requirements for records in electronic office environments (ISO, 2011) relates to electronic document and records management systems as well as enterprise content management systems. While it does not include specific requirements for digital preservation, it does acknowledge the need to maintain records over time and that format obsolescence issues need to be considered in the specification of these electronic systems.
There are international standards that are generic to good business management that may also be relevant in the digital preservation domain.
- Certification against ISO 9001 Quality management systems (ISO, 2015) demonstrates an organisation’s ability to provide and improve consistent products and services.
- Certification against ISO/IEC 27001 Information technology -- Security techniques -- Information security management systems (ISO/IEC, 2013) demonstrates that digital materials are securely managed ensuring their authenticity, reliability and usability.
- ISO/IEC 15408 The Common Criteria for Information Technology Security Evaluation (ISO/IEC, 2009) provides a standardised framework for specifying functional and assurance requirements for IT security and a rigorous evaluation of these.
There are a number of routes through which a digital preservation implementation can be certified. These range from light touch peer review certification methods such as the Data Seal of Approval, through the more extensive internal methods of DIN 31644 Information and documentation - Criteria for trustworthy digital archives (DIN, 2012), to the comprehensive international standard ISO 16363:2012 Audit and certification of trustworthy digital repositories (ISO, 2012a) (see Audit and certification).
Technical standards
There are specific advantages to using standards for the technical aspects of a digital preservation programme, primarily in relation to metadata and file formats.
In conjunction with relevant descriptive metadata standards, PREMIS and METS are de facto standards which will enhance a digital preservation programme. PREMIS (PREservation Metadata: Implementation Strategies) is a standard hosted by the Library of Congress and first published in 2005. The data dictionary and supporting tools have been specifically developed to support the preservation of digital material. METS (Metadata Encoding and Transmission Standard) is an XML encoding standard which enables digital materials to be packaged with archival information (see Metadata and documentation).
There are also standards relating to file formats. Choosing file formats that are non-proprietary and based on open format standards gives an organisation a good basis for a digital preservation programme. ISO/IEC 26300-1:2015 Open Document Format for Office Applications (ISO/IEC, 2015) provides an XML schema for the preservation of widely used documents such as text documents, spreadsheets, presentations. ISO 19005 Electronic document file format for long-term preservation (ISO, 2005) prescribes elements of valid PDF/A which ensures that they are self-contained and display consistently across different devices. Aspects of JPEG-2000 and TIFF are also covered by ISO standards. (see File formats and standards).
Barriers to using standards
A standards based approach to digital preservation is important, but there are also factors which inhibit their use as a digital preservation strategy:
- The pace of change is so rapid that standards which have reached the stage of being formally endorsed - a process which usually takes years - will inevitably lag behind developments and may even be superseded.
- Competitive pressures between suppliers encourage the development of proprietary extensions to, or implementations of standards which can dilute the advantages of consistency and interoperability for preservation.
- The standards themselves adapt and change to new technological environments, leading to a number of variations of the original standard which may or may not be interoperable in the long-term even if they are backwards compatible in the short-term.
- Standards can be intimidating to read and resource intensive to implement.
- In such a changeable and highly distributed environment, it is impossible to be completely prescriptive.
These factors mean that standards will need to be seen as part of a suite of preservation strategies rather than the key strategy itself. The digital environment is not inclined to be constrained by rigid rules and a digital preservation programme can often be a blend of standards and best practice that is sufficiently flexible and adapted to suit the needs of the organisation, its circumstances and the digital materials being managed.
Standards, best practice and good practice
In recent years best practice guidance and case studies have been published by national archives, national libraries and other cultural organisations. Digital preservation is also a topic well discussed on blogs and social media which can often provide real time information in relation to theory and practice from around the world. Papers at conferences such as iPRES, the International Digital Curation Conference (IDCC) and the Preservation and Archiving Special Interest Group (PASIG) can be a useful source of up to date thinking from academics and practitioners in digital preservation.
Standards should be understood as a formal description and recognition of what a community of experts might term best practice. Standards, and the best practice from which they derive can be intimidating and there is a risk for those starting in digital preservation that the ‘best becomes the enemy of the good’. So in adopting or recommending standards it should always be understood that some action is almost always better than no action. Digital preservation is a messy business which throws up unexpected challenges. So it is almost always the case that a poorly implemented standard is preferable to waiting for perfection.
Sector specific requirements
Specific industries have become active in the development of preservation standards, and particular types of content and use cases have emerged that overlap and extend a number of standards. There is considerable benefit in digital preservation standards being embedded in sector-specific standards since this will greatly assist their adoption, although this may present a challenge to coordination of activities. Three examples are given below:
- Audio visual materials present a special case for digital preservation (see Moving pictures and sounds). Recommendations for audio recordings and video recordings exist under the auspices of the International Association of Sound and Audio-visual Archives (such as IASA- TC04, 2009), while a range of industry bodies and content holders including the BBC, RAI, ORF and INA have formed the PrestoCentre to progress research and development of preservation standards in this field. https://www.prestocentre.org/
- The aerospace industry has particular requirements in product lifecycle management and information exchange which have given rise to a series of industry wide initiatives to standardise approaches to aligning and sharing CAD drawings for engineering. The membership body PROSTEP created the ISO 10303 ‘Standard for Exchange of Product Model Data’ which has developed into the LOTAR standard (http://www.lotar-international.org/lotar-standard/overview-on-parts.html). LOTAR is not incompatible with OAIS, but because it fits within a data exchange protocol important to the industry, aerospace engineers are more likely to encounter LOTAR than OAIS
- .The Storage Network Industry Association has also begun to make progress on the development of a series of standards. A SNIA working group on long-term data retention has responsibility for both physical and logical preservation, and the creation of reference architectures, services and interfaces for preservation. In addition, a working group on Cloud Storage is likely to become particularly influential in relation to preservation. Cloud architectures change how organizations view repositories and how they access services to manage them. For example, it is unclear how one would measure the success of a ‘trusted digital repository’ that was based in a cloud provider.
Resources
Seeing Standards; A visualisation of the metadata universe
http://jennriley.com/metadatamap/
The sheer number of metadata standards in the cultural heritage sector is overwhelming, and their inter-relationships further complicate the situation. This visual map of the metadata landscape is intended to assist planners with the selection and implementation of metadata standards. Each of the 105 standards listed here is evaluated on its strength of application to defined categories in each of four axes: community, domain, function, and purpose. (2010, 1 page).
Dlib Magazine
Dlib Magazine publishes on a regular basis a wide range of papers and case studies on the practical implementation of digital preservation standards and best practice. 
Core Trust Seal
https://www.coretrustseal.org/
PREMIS
http://www.loc.gov/standards/premis/
Library of Congress, 2015
The Digital Curation Centre
The Digital Curation Centre makes available research and case studies in relation to the preservation of research data. Iit also publishes recordings of its annual international digital curation conference proceedings.
The Signal
http://blogs.loc.gov/digitalpreservation/
The Signal is a digital preservation blog published by the Library of Congress
IPRES
http://www.ipres-conference.org/
IPRES, the International Conference on Digital Preservation publishes a website and proceedings from their annual event which looks at different themes within the digital preservation landscape,
The Digital Preservation Coalition Wiki
http://wiki.dpconline.org/index.php?title=Main_Page
The Digital Preservation Coalition Wiki provides a collaborative space for users of OAIS, the British Library’s file format assessments as well as other resources.
Digital Preservation Matters
http://preservationmatters.blogspot.co.uk/
The Digital Preservation Matters blog is a personal account of experiences from working with Digital Preservation
References
DIN, 2012. DIN 31644 Information and documentation - Criteria for trustworthy digital archives. Available: http://data-archive.ac.uk/curate/trusted-digital-repositories/standards-of-trust?index=3
IASA-TC04, 2009. Guidelines in the Production and Preservation of Digital Audio Objects: standards, recommended practices, and strategies: 2nd edition, edited by Kevin Bradley. Available: http://www.iasa-web.org/tc04/publication-information
ISO, 2001. ISO 15489:2001 Information and documentation -- Records management. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=31908
ISO, 2005. ISO 19005-1:2005. Document management -- Electronic document file format for long-term preservation. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=38920
ISO, 2006. ISO 20652:2006 Space Data and Information Transfer Systems - Producer-Archive Interface - Methodology Abstract Standard. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=39577
ISO, 2011. ISO 16175:2011 Principles and functional requirements for records in electronic office environments. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=55791
ISO, 2012a. ISO 16363:2012 Audit and certification of trustworthy digital repositories. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=56510
ISO, 2012b. ISO 14721:2012 Space Data and Information Transfer Systems - Open Archival Information System (OAIS) - Reference Model. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=57284
ISO, 2015. ISO 9001:2015 Quality management systems. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=62085
ISO/IEC, 2009. ISO/IEC 15408:2009 The Common Criteria for Information Technology Security Evaluation. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=50341
ISO/IEC, 2013. ISO/IEC 27001:2013 Information technology -- Security techniques -- Information security management systems. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=54534
ISO/IEC, 2015. ISO/IEC 26300-1:2015 Information technology -- Open Document Format for Office Applications (OpenDocument) v1.2 -- Part 1: OpenDocument Schema. Geneva: International Organization for Standardization. Available:http://www.iso.org/iso/home/store/catalogue_ics/catalogue_detail_ics.htm?csnumber=66363
ISO/TR, 2005. ISO/TR 18492:2005 Long-term preservation of electronic document-based information. Geneva: International Organization for Standardization. Available: http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=38716
Lavoie, B., 2014. The Open Archival Information System (OAIS) Reference Model: Introductory Guide (2nd Edition). DPC Technology Watch Report 14-02. Available: http://dx.doi.org/10.7207/twr14-02
Library of Congress, 2015. METS Metadata Encoding and Transmission Standard. Available: http://www.loc.gov/standards/mets/