Introduction

From preserving research results to storing photos for the benefit of future generations, the importance of preserving digital data is gaining widespread acceptance. But what about software?

It is easy to focus on the preservation of data and other digital objects, such as images and music samples, because they are generally seen as end products. The software that is needed to access the preserved data is frequently overlooked in the preservation process. But without the right software it could be impossible to access the preserved data – which undermines the reason for storing the data in the first place.

A key challenge in digital preservation is being able to articulate, and ideally prove, the need for preservation. There are different purposes and benefits which facilitate making the case for preservation. These should be combined with preservation plans regarding data and hardware: digital preservation should be considered in an integrated manner. For example, media obsolescence and recovery is often as much a part of a software preservation project as a data preservation project.

The Software Sustainability Institute (SSI) in partnership with Curtis+ Cartwright Consulting have developed a series of outputs to support the sector by raising awareness of software sustainability and preservation issues, as part of a Jisc-funded initiative. In particular a benefits framework has been published that can help groups understand and gauge the benefits or drawbacks of allocating effort to ensuring that preservation measures are built into processes, and to promote actively preserving legacy software. The rest of this chapter provides a summary of advice based on this work.

When should you consider software preservation?

Software is used to create, interpret, present, manipulate and manage data. There is no simple and universally applicable formula for determining if your software needs to be preserved, and how to go about preserving it. Instead there are a range of questions and factors which should be taken into account. In particular, curators should consider software preservation whenever one or more of the following statements is/are true:

The software cannot be separated from the data or digital object

In an ideal world, data can be isolated and preserved independently of the software used to create or access it. Sometimes this is not possible. For example, if the software and the data form an integrated model, the data by itself is meaningless.