Section 8 Example Argument Template

8.1 Introduction

This Section provides information to facilitate a clear structured approach for developing software safety arguments. Furthermore, it provides clarification on which aspects fall within and outside of the scope of the NS Software Rules.

Please note that it is a generic argument structure and should be used for information purposes only. The main intention is to provide an example of how a potential software argument can be presented. It does not replace the requirements specified in the NS Software Rules.

Goal Structuring Notation (GSN), a graphical argumentation notation, has been used to develop the generic argument structure in Figure 1.8.1 GSN Generic Argument Example (part 1) to Figure 1.8.4 GSN Generic Argument Example (part 4) below. Information on GSN can be found in the GSN community standard, at http://www.goalstructuringnotation.info/. The standard seeks to provide a comprehensive, authoritative definition of the Goal Structuring Notation (GSN) and it also aims to provide clear guidance on current best practice in the use of the notation for those concerned with the development and evaluation of engineering arguments – argument owners, readers, authors and approvers. For those unfamiliar with GSN it is recommended that you familiarise yourself with the basic principles and notations described on the GSN Standard before reading the example argument template.

Where appropriate, colour coded boxes have been used in the diagrams to provide supporting comments.

Section 8 Example Argument Template

8.1 Introduction

Figure 1.8.1 GSN Generic Argument Example (part 1)

Figure 1.8.2 GSN Generic Argument Example (part 2)

Figure 1.8.3 GSN Generic Argument Example (part 3)

Figure 1.8.4 GSN Generic Argument Example (part 4)