Transcript The Rare Glitch Project: Verification Tools for Embedded Systems Ed Clarke, David Garlan, Bruce Krogh, Reid Simmons, Jeannette Wing Carnegie Mellon University Pittsburgh, PA.

The Rare Glitch Project:
Verification Tools for Embedded Systems
Ed Clarke, David Garlan, Bruce Krogh,
Reid Simmons, Jeannette Wing
Carnegie Mellon University
Pittsburgh, PA
Embedded Systems
 They are highly distributed, multi-task, concurrent
real-time systems.
 They control increasingly sophisticated physical
systems.
 They operate with increasing autonomy under
adverse and unpredictable conditions.
 They eventually will be seamlessly woven into the
fabric of our everyday lives.
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Verification
 Grand Challenge
 To ensure the correctness of these embedded systems as
they operate in increasingly complex environments—for the
safety and good of the general public.
 Opportunity
 State of the art verification tools are well suited for control
systems.
 Embedded systems have narrow hardware/software
interface.
 Embedded systems architectures are simpler and more
regular.
 Feasibility
 We are not trying to solve the whole verification problem, but
one for a class of systems for which we believe we can make
the next big success story.
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Our Long-Term Vision
 To provide design engineers with lightweight “pushbutton” tools, each checking a specific applicationspecific property.
Check
Check
Restart
Deadlock Race
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Check
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Check
Check
Power
usage
Fuel
usage
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Three Main Thrusts of Our Project
system
environment
 Verifying system integrity
Synchronization constraints
 Resource constraints
 Real-time constraints

 Modeling the environment
Hybrid dynamics
 Stochastic models

 Usability
Extracting models
 Explaining tool feedback

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Technical Challenges
 Interleavings of multiple task executions
 Inter-task dependencies and synchronization
requirements
 System resource constraints
 Hard real-time constraints
 Interactions with complex physical dynamic systems
 Adverse, unpredictable environments
 Stringent requirements for autonomy, fault tolerance,
and survivability
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Technical Approach
Embedded System
Environment
Design Engineer’s Verification Toolbox
Usability
System Integrity Properties
Synchronization
Constraints
Resource
Constraints
Modeling the Environment
System-Environment Modeling Uncertainty:
Interactions: Hybrid
Stochastic Models
Dynamics
Real-time
Constraints
Foundational Building Blocks
Model checking techniques and tools
Task-level system architecture, task executive languages
Continuous dynamics, quantitative analysis, reliability analysis
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Cross-Cutting Themes
 Exploit model checking techniques and tools.
 Focus on the task level.
 Incorporate continuous domains in our models.
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Verifying System Integrity
 Synchronization constraints
 Publish-subscribe
architecture
 Cyclic-tasks with shared variables

Research question: How can we reason about their aggregate
behavior?
 Resource constraints
 Continuous,
consumable (e.g., fuel) and
renewable (e.g., bandwidth, disk space)
resources

Research question: How should we specify and verify resource
constraints?
 Real-time constraints
 Quantitative

timing analysis
Research questions: How can we extend this technique to
continuous time? How can we deal with dynamic process
creation and deletion?
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Modeling the Environment
 Hybrid dynamics
 Dealing
with both discrete and continuous state
variables

Research question: How can we automate and scale differential
equations models for large systems?
 Stochastic models
 Dealing
with uncertainty, unpredictability
 Using continuous variables (e.g., probabilities) for
reliability and cost-benefit analyses

Research questions: How can we handle dependent events,
cascading of events? Both nondeterministic and probabilistic
state transitions?
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Usability
 Extracting models
 Synchronization
skeletons
 Translators for task execution languages

Research question: How can we balance expressibility of
languages with efficiency of verification and user-friendliness?
 Explaining verification tool results
 Adopt
AI techniques to explain counterexamples for
task executive programs.
 Develop techniques to view and browse the temporal
evolution of counterexamples.

Research question: How can we create virtual execution traces
that can be used by existing visualization tools?
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The Rare Glitch Tool Suite
Checkers and Provers
Specification and
Modeling
Languages
Specification
Analysis Engines
Checkmate
Reliability and
Cost Analyzers
Prism
SMV
Counterexamples
Explanation
Generator
Model
PVS
Abstraction/
Refinement
Processor
Symp
…
…
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Preliminary Planning
 Technical
 So
far: Technical presentations of our current work
 To do


Identification of case studies
Identification of common group project
 Continue
to pursue existing two-way and three-way
collaborations
 Administrative
 Weekly
project meetings, project name, project web
page
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Project Administration
 Principal Investigators
 Ed
Clarke, David Garlan, Bruce Krogh, Reid Simmons,
Jeannette Wing (POC)
 Industrial connections
 Honeywell
Technology Center
 CMU High Dependability Computing Consortium
 Years 3 and 5
 Hold
workshops for technical exchange with industry
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Preview of This Afternoon’s Talks
 Ed Clarke
 Verifying
Bus Protocol Standards for Embedded
Systems
 Bruce Krogh
 Model
Checking for Hybrid Systems
 Jeannette Wing
 Scenario
Graph Generation and MDP-Based Analysis
 David Garlan
 Model
Checking Publish-Subscribe Software
Architectures
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