Preservation Strategies

Migration

Migration (reformatting and refreshing) is a solution to media obsolescence or deterioration. There are several levels of migration. Maintaining the original integrity and functionality of the work, you can transfer hardware and software to a new operating system or you can transfer an obsolete file format to a new format.

Emulation

Emulation involves the re-creation of the technical environment required to view an object. This is achieved by maintaining information about the hardware and software requirements so that the system can be reengineered by future systems to emulate the original environment. This approach means you do not need to migrate files, but emulators must be created for every software and hardware configuration, which can be expensive.

Encapsulation

Encapsulation groups a digital object with all components that are necessary to provide access to that object. In encapsulation, physical or logical structures called "containers" or "wrappers" provide information about the relationships between all data and software application components. Encapsulation aims to overcome the issue of obsolete file formats by including details on how to interpret the original information and possibly re-create the original work.

It is critical to document all preservation actions and experiments in the catalog. Although the archivist should avoid making changes that compromise the overall functionality or "look and feel" of the work, any changes that occur, if at all, should be thoroughly documented and explained.

For more information on migration and other preservation strategies, see Cornell University Library's Digital Imaging Tutorial and the National Archives of Australia's digital preservation strategy.

See IMAP's list of case studies of digital preservation