Introduction

The digitization of valued original materials is often undertaken with the dual goals of both improved access and enhanced preservation (Kenney, 1996, 3). However, the preservation is often secondary, preserving only by reducing the physical access to the original. The digital version is generally not considered to be a primary preservation resource. Important as the preservation of originals through digitization is, these originals are unlikely to be at such immediate risk as the data and digital resources themselves, with ‘born-digital’ data being in the highest risk category. This chapter will cover all these topics, starting with a discussion of the scale of the digital preservation problem, then examining some key issues in preservation in the analogue world for libraries and archives, which offer concepts and models that need to be considered and adopted in the digital world. We then address the numerous issues attendant upon digital data preservation, and evaluate some international, national and institutional initiatives for the preservation of digital data.

Throughout this chapter, we differentiate between data preservation (which is about ensuring full access and continued usability of data and digital information), and preservation through digitization (which allows for greater physical security of physical analogue originals). Strategically it becomes self-evident that to reduce the stress upon the valued original, the data created must last as long as possible. Thus processes and intentions for preservation must be decided early in the digital lifecycle (see Chapter 2 ‘Why digitize?’) to ensure that repeating the digitization directly from the original is reduced or hopefully eradicated – though we will show below that costs of digital data storage can mean that it may sometimes be cheaper to return to the originals.

This chapter will discuss the following issues:

• • the scale of the digital preservation problem

• • preserving the written heritage

• • preservation through surrogacy

• • authenticity of digital data

• • surrogate versus original

• • digital surrogacy: is it a preservation alternative?

• • why data needs preservation

• • how digital data is to be preserved

• • methods of preservation of digital materials