Introduction

In 2003 the National Library (KB) started developing a Preservation Subsystem for the e-Depot, based on the KB/IBM report Preservation requirements in a deposit system (Long-Term Preservation Study 3). This system consists of a Preservation Manager, a Preservation Processor and tools for permanent access. The Preservation Manager uses technical metatadata to manage and control the long-term preservation of the digital objects stored in the e-Depot.

Preservation Layer Model and View Paths

The Preservation Manager registers information on the file formats stored in the e-Depot, using a structure consisting of Preservation Layer Models (PLM) and View Paths. A Preservation Layer Model describes the different layers on which the software runs. For instance, a PLM can consist of the following layers: data format, viewer application, operating system and reference platform. The separate layers can be specified with attributes such as “Name operating system”, “version” and “patches”.
Figure 1: Preservation Layer Model
A View Path describes what the PLM actually consists of, such as the name of the operating system, the version number and the hardware specifications that are required to run the operating system. The more View Paths there are for a certain file format, the better its chances of survival.

Figure 2: View Path

Implementation

The project was carried out with IBM, which also developed the DIAS system for the e-Depot. In April 2004, a stand-alone version of the system was realised. This version has been evaluated and is now being improved. In 2006, the new version will be integrated into the DIAS system. When this is achieved, the KB will be able to anticipate when the long-term accessibility of certain objects from the e-Depot is at risk. In addition, the KB aims to exchange information with other users and to keep abreast of international developments to improve the Preservation Manager further.

Contact

For more information please contact Barbara Sierman