Open source components in safety critical systems

Suvi-Maaret Suomalainen

7.12.2004

Content

• Introduction

• QA for safety critical system

• QA in open source development

• Examples

• Conclusions

Introduction (1/2)• Background

- use of safety critical system- closed automation system- quality of OSS

• Motivation- closed system- few suppliers- high prices

Introduction (2/2)• Research Problem and objectives

– Can components of the safety critical software be open source components?

– Comparing OSS quality assurance to the requirements of IEC 61508

• Method– Literature study– INSPEC and IEEE databases

• Scope– European IEC 61508– Verification methods– No hardware requirements

QA for safety critical system• Safety plan

– software lifecycle• Testing

– test plans in early phases– documentation– test tools and environments– testing independence

• Testing techniques– dynamic– static– modeling

QA in open source projects• No project plan

– good configuration tools– change management differs

• No testing plans• Different techniques• Testing independence• No documents• Highly motivated developers

Examples• Most used Linux (OS and real time OS)

– CVS repositories– Bug database– Documentation volunteer work

• Others used in user interfaces and specification tool (not so safety critical)

• NASA experiences– Project maturity– Project longevity– Flexibililty

Conclusions• Differences between IEC 61508 and OSS

– test plans– testing techniques mainly dynamic– documentation– change management

• OSS can’t be used as such– management for the developer of the safety

system– testing and documenting…