How can digital objects be preserved?

Like print publications, digital objects can also deteriorate, whether in part or as a whole. Single bits on a hard drive can become defective, making it impossible to read objects correctly. Conservation measures at bitstream level are known as bitstream preservation.

In many cases, the software used to retrieve the data and make it readable becomes obsolete as new versions are developed. One of our central tasks is therefore to ensure that older data can still be interpreted in changing system environments.

Two processes are commonly used for this purpose (long-term archiving strategies):

1. Migration: The file format of the digital object is converted for use in the display programs available in the current system environments.

2. Emulation: Special software (emulators) is used in a current system environment to reconstruct a suitable, usually older environment in which the digital object can again be used.

Both of these processes are complex and entail a risk of unintentional information loss that may go unnoticed.

We can assume that every digital object will become unusable at some point if neither of these processes are implemented.

The processes have specific advantages and disadvantages depending on the type of digital object. Both processes are used for our collections.

Which measures do we use?

Bitstream preservation

The German National Library transfers the digital objects in its collections to a digital long-term archive. This is hosted and maintained by the service provider GWDG (Gesellschaft für wissenschaftliche Datenverarbeitung Göttingen). GWDG uses appropriate processes such as redundant storage and data checks to ensure lasting data consistency in the long-term archive.

Migration

Our digital long-term archiving system facilitates precise data format migration by means of object versioning and automatically retrievable technical metadata. We use this information on a regular basis to identify the need for conservational measures and implement the migrations in internal projects.

Emulation

The emulation of older system environments is required for interactive computer programs in particular. An automatic emulation system is used so that these digital objects can be made available in the reading rooms.

Further Information

Long-term Preservation Policy