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Six Months In Praxis. Bill J Ellis. Dependable Systems Group School of Mathematical & Computer Sciences Heriot-Watt University Edinburgh. (On secondment at) Praxis High Integrity Systems Bath. Overview. Context NuSPADE Proposal Architecture Results SPADEase Proposal Conclusions.
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Six Months In Praxis Bill J Ellis Dependable Systems Group School of Mathematical & Computer Sciences Heriot-Watt University Edinburgh (On secondment at) Praxis High Integrity Systems Bath
Overview • Context • NuSPADE • Proposal • Architecture • Results • SPADEase • Proposal • Conclusions
Context 2001 • NuSPADE: 2001 2004 • EPSRC critical systems programme (GR/R24081) • Collaboration with Praxis • SPADEase: Jan 2005 July 2005 • EPSRC research assistant industrial secondment scheme (GR/T11289/01) • Direct follow-on to NuSPADE • Secondment to Praxis • PhD: 2001 2005…? • Research directly related to NuSPDE • Now writing up… Principle investigator (and PhD supervisor): Andrew Ireland 2002 2003 2004 2005 2006
NuSPADE Investigate the role of proof planning within the SPARK approach to high integrity software • Proof planning: • Strong paradigm for exploring proof techniques • Previous results in proving loop verification conditions (VCs) • SPARK approach to high integrity software: • Gain immediate access to VCs • Potential for industrial analysis
Completing Proof in SPARK SPADE Simplifier Remaining VCs SPADE User Program properties Proof Script Code and specification SPADE Proof Checker
Introducing NuSPADE SPADE User SPADE Simplifier Remaining VCs NuSPADE Program properties Proof Script Proof planner Program analyser Code and specification SPADE Proof Checker
NuSPADE Results • NuSPADE • Evaluation based on examples from literature and industrial data provided by Praxis (SHOLIS) • Focus on: • Exception freedom VCs • Not automatically proved by the Simplifier • Typically these arise from loop based code • 80% of such problems were provable using our techniques • However • NuSPADE is a typical academic system…
SPADEase Towardsincreased verification automation for high integrity software engineering • Towards: • Six months is not long enough for a complete system • Increased verification automation: • Exploit the results of the NuSPADE project • With an emphasis the practical task of automation • High integrity software engineering: • Secondment at Praxis (High Integrity Systems)
Introducing SPADEase VCG • SPADEase • Automatically prove additional VCs • Same external behaviour as the Simplifier • Focus on proof planning (over program analysis) • Implementation • Tweaks to Simplifier (completed) • Tweaks to Proof Checker (first draft completed) • Overhaul of NuSPADE (just starting…) • Problem loading mechanism • Data management system • Evaluation • Compare with NuSPADE • Explore new examples SPADEase SPADE Simplifier SIV Refined NuSPADE SIV
Conclusions • Building upon NuSPADE • To develop a new SPADE proof tool (SPADEase) • Feedback welcome • Training opportunities? • Interesting proof examples? http://www.macs.hw.ac.uk/spadease/