Digital preservation

Digital preservation ensures that digital resources remain accessible from one generation to the next. 

Digital preservation means that digital information is preserved as understandable and usable for decades and even centuries. The preservation of information must be secured, even though over time devices, software and file formats become obsolete. From the perspective of preservation, the lifespan of a publication should be considered already at the time of its creation.   

The digital preservation of online materials collected and cultural heritage materials digitised by the National Library is carried out in cooperation with CSC – IT Centre for Science OY, using their Digital Preservation Service for Cultural Heritage. The Digital Preservation Service for Cultural Heritage is a suite of services offered by the Ministry of Education and Culture to cultural heritage organisations to enable the preservation of their digital resources. The service ensures the digital preservation of the central national digital information resources of libraries, archives and museums. 

Digital preservation is roughly divided into three levels: bit-level, logical and semantic preservation.  

Bit-level preservation ensures that files remain unchanged regardless of time and place. This requires actively monitoring file integrity by comparing file copies stored in the digital preservation service, fixing corrupted files, refreshing preservation technologies (such as renewing disk systems when needed) as well as geographically decentralising the material. Bit-level preservation is the foundation of digital preservation. In the digital preservation service, it is ensured by preserving all materials in multiple copies in different systems.

The goal of logical preservation is to enable the future use of the resources, meaning that future software must accordingly be capable of opening and interpreting the files. Consequently, the digital preservation service accepts only file formats that can be migrated through logical preservation (i.e., converted into another format). The primary method of software preservation is emulation, which means mimicking the original operating environment in a more modern hardware environment. At present, the digital preservation service does not provide emulation.

In the likelihood of preserved resources becoming technically obsolete, the material will primarily be migrated. Migrations are formulated collaboratively by the National Library and CSC – IT Centre for Science so that the key features of materials documented at the collection level in the preservation plan do not change substantially. These features are defined according to the requests and requirements of the designated community. They can change both over time and when the designated community itself changes.

Semantic preservation focuses on retaining the intelligibility of the materials, which requires an in-depth knowledge and understanding of both the target designated community and the materials. Even though the resources may be preserved as intact and generally usable, it may be impossible to use them in the future if their content is incomprehensible. 

One example of the challenges of semantic preservation relates to the translation into Finnish of the Latin-language doctoral theses of the Royal Academy of Turku: although the original designated community understood Latin, the current one generally does not. The semantic preservation of this material would require offering researchers not only the material, but also Latin grammar and vocabulary.

For digital preservation, online material and electronic publications must be in transferable or preservable file formats. Further information is available in the specification document for the Digital Preservation Service for Cultural Heritage released by CSC: https://digitalpreservation.fi/specifications/fileformats. In addition, all material must be described in the Finnish National Bibliography or the National Library’s Fikka database for digital preservation.