Introducing Significant Properties Stephen Grace and Gareth Knight Centre for e-Research

2 Overview of KeepIt session Introduction to Significant Properties InSPECT methodology Practical exercise in object analysis Practical exercise in stakeholder analysis Implementing SPs in an archive Summary

3 Why Significant Properties? The fundamental challenge of digital preservation is to preserve the accessibility and authenticity of digital objects over time and domains, and across changing technical environments Wilson, 2008 If we change something in order to keep it safe, how do we know we can trust the results?

4 Significant Properties timeline 1999 Clifford Lynch– canonicalisation CEDARS – significant properties –those components of a digital object deemed necessary for its long-term preservation CAMiLEON – significant properties –those properties of digital objects that affect their quality, usability, rendering, and behaviour 2002 Thibodeau – essential properties or characteristics cont/

5 Significant Properties timeline 2008 InSPECT – significant properties –the characteristics of digital objects that must be preserved over time in order to ensure the continued accessibility, usability, and meaning of the objects 2008 PLANETS – Plato utility analysis and XCL 2009 Dappert/Farquhar – significant characteristics –custodians must focus their attention on preserving the most significant characteristics of the content, even at the cost of sacrificing less important ones 2009 Todd – significant properties

6 Authenticity, integrity, viability the characteristics of digital objects that must be preserved over time in order to ensure the continued accessibility, usability, and meaning of the objects Authenticity – is this what it purports to be? Integrity – is this complete and unaltered? Viability – is this suitable for its audience (aka Designated Community)?

7 Representation Information in OAIS Representation Information consists of: Structure information that describes the encoding scheme in which data is stored, e.g. format, encoding algorithm Semantic information that indicate how the values are to be interpreted. E.g. documentation that indicates how numeric values in a CSV or tab-delimited format must be interpreted.

8 Interpreting SPs in abstract NAA Performance Model OAIS Reference Model

9 Interpreting SPs in practice NAA Performance Model data = information content computer + OS + + application

10 Significant Property types Content: conveys information, not necessarily human readable Context: background information on technical and business environments to which the digital objects relate Rendering: how the content of the object appears or is recreated, e.g. audio or visual Structure: component parts of the object and how they relate to each other Behaviour: functionality that is intrinsic to an object

11 Compare and contrast

12 Compare and contrast

13 SPs used in digital preservation Document technical properties Describe intellectual entities Determine preservation priorities Measure the success of transformations