Migration of older digital records at the Danish National Archives.

Migration of older digital records at the Danish National Archives.

The Danish National Archives has completed a major migration project of all digital records received before 2000. An evaluation report has now been published in English. It is available here:


The Danish National Archives is very interested in knowing if any other preservation institutions have accomplished or plan to accomplish similar projects. We would also be very interested in any comments about the project and the evaluation report.

Abstract of the report:

The Danish National Archives has ingested digital records since 1973. These digital records were migrated into a preservation standard created in 2000 with a slight revision in 2004. The main objectives of this operation were to save data from technological obsolescence and to reduce the cost of access and future migrations by enabling automatic processing of the data.

The migration project cost approximately 30 FTEs (Full-Time Equivalent), and the total cost of software, hardware and external services amounted to around 135.000 Euros.

The project migrated data from relational and hierarchical databases and electronic records management systems (ERMS). It included the digitisation of audio and video as well as paper documentation. The databases comprised for example the first Civil Registration System from 1968 and the State Tax Administration’s final equation from 1970.

Data and documentation made up a total of about 1.7 TB, consisted of 11,187 files in almost 200 different structures, and constituted more than 2,000 information packages.

The preservation standard defined the overall technical objectives of the migration which were:

  • Common format for data files
  • Common structure of documentation, metadata and documents
  • Common format for documents (TIFF)

 It was possible to migrate 100% of the more recent records (records received after 1998) and 87% of the older records in an automated fashion. The remaining 167 information packages had to be pre-processed before they could be migrated automatically. 175 small programs were developed for this pre-processing.

The project achieved its main objectives, since all the digital records in question were migrated.

Access and future migrations of the records have also become easier. However, a fully automatic processing of the collection is not yet entirely possible.

The overall conclusion is that the migration project, which is the first of its kind, was of very high quality, both in terms of planning, execution and product.

A few main conclusions are: 

  • Standardisation of data is a prerequisite for an economically sound digital preservation: It took about 70 times longer to migrate an older, non-standardised information package, than a newer, standardised one.
  • Inadequate feasibility studies remind us that the timing in digital preservation saves money: The condition of the magnetic tapes was examined through spot checking 10 years prior to the migration project and found satisfactory, which turned out to be an erroneous, expensive conclusion. 
  • The technical infrastructure suffered from a number of shortcomings and late decisions, resulting in precious loss of time.


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