Modular Emulation

Digital objects are vulnerable. The question of which is the best method for preserving and retaining access to digital information has already been the subject of worldwide discussion for several years and will, without doubt, continue to be discussed for several more years to come. Research into several different types of strategy is ongoing; emulation is one of those strategies.

Emulation maintains permanent access to records by recreating a suitable environment on future computing platforms in which original files can be rendered. This means the file format and bitstreams are not altered in any way and the authenticity and integrity of the files over time is maintained. This is quite different to migration, which involves conversion of the files into newer formats that can easily be read on different (and future) computing platforms.

Objectives and products
The goal of the project is the development of an open source, easily portable and modular emulator. The image below is a conceptual model of the modular emulator.

At the centre of the model is the modular emulator on which the original operating system and application software can be run. The emulator consists of separate modules that each emulate a specific function, such as a CPU, RAM memory, hard disc, graphics card, etc.

Each module can be re-used in different emulation scenarios. All modules are saved in a so-called 'module library'. An emulator specification document describes which modules must be used in a given scenario; the technical administrator will use this document to install the required modules and the emulator is created 'on the fly'. A Universal Virtual Machine (UVM) runs on existing hardware and operating system so that the emulator is not dependent upon a particular combination of hardware and operating system. The modular approach reduces the effort required to adapt the machine for a different type of emulation, because it is possible to re-use modules or add new modules. The portability of the developed emulator is enhanced by use of a 'tussenlaag' – cushioning layer. A Java Virtual Machine (JVM) serves that purpose in this project.

Planning
The project started in April 2005 with a preliminary analysis and a feasibility study. Development of the emulator began in February 2006. The project will run until April 2007.

Participants
The National Archive and the Royal Library (KB).
Contact person at the National Archive - Remco Verdegem (project leader) remco.verdegem@nationaalarchief.nl
Contact person at the KB - Jeffrey van der Hoeven (test team coordinator and member of the development team) - jeffrey.vanderhoeven@kb.nl

Written statement concerning the use of emulation for digital preservation
On October 20th 2006, the modular emulation project team organised an expert meeting attended by national and international emulation experts. This meeting resulted in publication of a written statement on the use of emulation for digital preservation.