Long-term Digital Archiving

As well as maintaining historical records since the 9th century, the Institute for the History of Frankfurt preserves contemporary records for the benefit of future research. We therefore continually accept documents from the City Council – material which now also includes more and more digital data. Many public authorities have used their own digital procedures for quite a while now – since the 1970s and 1980s, e.g. an electronic population register. The 1990s saw an increasing use of PC workstations – something is now part of everyday life.

In February 2015, the Institute was the first public body in the state of Hesse to set up a long-term digital archive called DiMag with the intention of preserving digital records “for eternity”. DiMag was originally developed by the State Archives of Baden-Württemberg and is now used by five other federal states, including the Hessian State Archives. Working under the provisions of the Hessian Archives Act, the Institute for the History of Frankfurt welcomes both analogue documents and digital records created by departments and public authorities. This includes both file storage and a large number of specialist administrative procedures (i.e. databases).

DiMag translates the preservation procedure for analogue documents – e.g. ensuring proper storage and access control – into the world of digital data. Under the DiMag system the relevant meta data of archived items are managed under a database and the resulting files and metadata are backed up independently of that database. Whenever the Institute receives a digital item, for instance a map of the city, we start by entering the meta data into the database. Next, we upload both the original file and the meta data into our digital magazine. We also check whether the file format actually allows archiving or whether it should first be converted to a different format. A Word file, for instance, is first converted to PDF/A. When a file is uploaded, the system generates a checksum – a so-called hash value – which is regularly checked and provides information whether anything has changed in the available data. Files are first saved to a virtual server at Office No. 16 and then to the systems of two Frankfurt City data centres. In addition, the material is backed up on tape. These measures and regular data migration to a new, contemporary format serve to ensure that our files are available “for eternity”.