streams are some practices to attempt to ensure the authenticity of digital objects. STRATEGIES FOR DIGITAL PRESERVATION As for preservation strategies, there is no ‘one-size-fits-all’ strategy for digital preservation. A range of strategies that are appropriate to different categories of digital material may need to be used. Common approaches to digital preservation are: 1. Technology preservation – this approach involves preserving the original software that was used to create and access the information, and preserving both the original operating system and hardware on which to run it. This strategy is not considered feasible over the long term, though it can be useful to keep one or two generations of earlier software and/or hardware. 2. Emulation – this approach involves emulating older software and hardware, using modern computers. Emulation requires significant resources and technical expertise and is generally not a viable option in small to organisations. 3. Migration – this approach involves transforming the digital information into new formats before the old format becomes obsolete, preserving the intellectual content of the information and retaining the ability of users to retrieve, display and use the information. Of these three approaches, migration is the most reliable, cost-effective and commonly used digital preservation strategy, and is explained in more detail on pages nine to 10 that follow. Backing up digital information It is very important to back up your organisation’s digital information to prevent the loss of this information in the case of a disaster. Backing up involves copying information onto different storage media, such as a separate hard drive or tapes. Always hold at least two copies of information, a working copy and a back-up copy, preferably off site.
desired purpose, subject to certain conditions of use. Although open formats are generally preferable for digital preservation purposes, just because a format is open it does not necessarily mean that it is good. A good indicator of the quality of an open format is the extent of adoption of that format by organisations and members of the community. Open formats and proprietary formats are explained further below. Open format Open proprietary format Closed proprietary format Examples Portable Network Graphics (PNG), OpenDocument Format (ODF), JPEG, Extensible Hypertext Markup Language (XHTML), Tagged Image File Format (TIFF), Free Lossless Audio Codec (FLAC), Portable Document Format (PDF) - ISO 32000. MP3 Microsoft Office Open XML – eg Docx (OoXML, also issued as ECMA standard 376 and ISO 29500 transitional). Microsoft Word (DOC), Microsoft Outlook, Excel (XLS), PowerPoint (PPT), Photoshop (PSD), Microsoft Access, RAW image formats, WAV audio format. What is it? Publicly shared intellectual property, usually maintained by a standards organisation. Privately-owned intellectual property. Privately-owned intellectual property. Availability of the format specification Specification published without any restrictions. Specification may be made available with restrictions. No specification publicly accessible. How is it developed? The format is developed through a publicly visible, community-driven process. The format is developed and marketed by companies which control the way the technology is used, to improve their market position. The format is developed and marketed by companies which control the way the technology is used, to improve their market position. How can it be used? Can be used and changed by anyone without restrictions, except for licensing conditions that may limit development of commercialised versions of software. Licence holder has exclusive control of the technology to the (current or future) exclusion of others. License holder has exclusive control of the technology to the (current or future) exclusion of others.
What software is needed to use it? Open formats are free to be implemented by anyone, including both proprietary and free and open source software, using the typical licenses used by each. Generally only licensed applications are free to use these formats. Proprietary file formats can only be accessed using the software that produced that file, or licensed applications. Conclusion Open formats, which are supported by a wide range of software or are platform-independent, are recommended for use where possible. Open formats support long-term sustainability of data by allowing migration from one technical environment to another, without locking into a specific vendor. Open proprietary formats are a greater risk than open formats because they are controlled by a corporate entity under licensing arrangements that may change. Proprietary formats carry greater risk to long-term accessibility of the data they hold. The lack of documentation of the specification, and licensing requirements for software means the format is less APPENDIX B – TOOLS FOR DIGITAL PRESERVATION are many solutions available for harvesting, identifying and managing data – including a number of free and open source tools. All solutions require – at the absolute minimum – one computer workstation, a staff member with computer experience to implement the software and import and manage data, and storage for data (two hard drives at the very least). Open-source digital preservation tools Name What does it do? Who use it? HOPPLA (Home and Office Painless Persistent Long-Term Archiving) HOPPLA is free and can be downloaded for free at . Released publicly September 2010 HOPPLA provides a set of different strategies for preservation of digital data, including back-up and migration. HOPPLA copies files to different locations and converts some of these copies to other formats if there is a risk that the original source file will become obsolete. The tool can handle documents, personal photos and/or videos and digital music collections. Private users and small organisations that know they need a digital preservation system but don’t have the skills or knowledge to develop one. National Archives of Australia’s Digital DPSP migrates data from its original format into open, fully Larger,
Preservation Software Platform (DPSP) The source code and support documentation for DPSP is free and available at . documented formats for archival preservation. The DPSP tools comprise Manifest Maker (which creates a list of digital files and directs it to a specified location), XENA (which converts files to open format standards), Digital Preservation Recorder (the workflow tool which ingests and stores files), and Checksum Checker (which monitors the contents of the digital archive for corruption). DPSP is a repository system, which interfaces with the National Archives’ collection management database, and uses the unique barcode applied to the file by the organisation. organisations with access to professional ICT skills and good ICT infrastructure. Archivematica ) Archivematica is a different system to the repository-based DPSP. Instead of using a complex database or external control system that tracks the links between the object and its metadata, it uses one system where the object and metadata stay in the same file system. The simplicity of Archivematica makes it ideal for organisations with limited financial and technical capacity. Platform or framework tools (software applications that work as building blocks for a digital archive) Fedora Commons (Flexible Extensible Digital Object and Repository Architecture) Fedora provides a digital asset management (DAM) architecture, upon which many types of institutional repositories, digital archives, and digital library systems can be built. It is widely used, open-source software that can be run on different operating systems, but requires a lot of technical expertise to implement adequately. Larger, organisations with access to professional ICT skills and good ICT infrastructure. DSpace DSpace provides the tools for the management of digital assets and a platform for preservation activities. It is also open-source, offers a repository system that can handle a wide range of digital objects, can be run on different Educational institutions needing to manage large quantities of digital resources.