1 The Real-Time Environment
1.1 When Is a Computer System Real-Time?
1.2 Functional Requirements
1.2.1 Data Collection
1.2.2 Direct Digital Control
1.2.3 Man-Machine Interaction
1.3 Temporal Requirements
1.3.1 Where Do Temporal Requirements Come From?
1.3.2 Minimal Latency Jitter
1.3.3 Minimal Error-Detection Latency
1.4 Dependability Requirements
1.4.1 Reliability
1.4.2 Safety
1.4.3 Maintainability
1.4.4 Availability
1.4.5 Security
1.5 Classification of Real-Time Systems
1.5.1 Hard Real-Time System Versus Soft Real-Time System
1.5.2 Fail-Safe Versus Fail-Operational
1.5.3 Guaranteed Response Versus Best Effort
1.5.4 Resource-Adequate Versus Resource-Inadequate
1.5.5 Event-Triggered Versus Time-Triggered
1.6 The Real-Time System Market
1.6.1 Embedded Real-Time Systems
1.6.2 Plant Automation Systems
1.6.3 Multimedia Systems
1.7 Examples of Real-Time Systems
1.7.1 Controlling the Flow in a Pipe
1.7.2 Engine Control
1.7.3 Rolling Mill
Bibliographic Notes
Review Questions and Problems
2 Simplicity
2.1 Cognition
2.1.1 Problem-Solving
2.1.2 Definition of a Concept
2.1.3 Cognitive Complexity
2.1.4 Simplification Strategies
2.2 The Conceptual Landscape
2.2.1 Concept Formation
2.2.2 Scientific Concepts
2.2.3 The Concept of a Message
2.2.4 Semantic Content of a Variable
2.3 The Essence of Model Building
2.3.1 Purpose and Viewpoint
2.3.2 The Grand Challenge
2.4 Emergence
2.4.1 Irreducibility
2.4.2 Prior and Derived Properties
2.4.3 Complex Systems
2.5 How Can We Achieve Simplicity?
Points to Remember
3 Global Time
3.1 Time and Order
3.1.1 Different Orders
3.1.2 Clocks
3.1.3 Precision and Accuracy
3.1.4 Time Standards
3.2 Time Measurement
3.2.1 Global Time
3.2.2 Interval Measurement
3.2.3 π/δ-Precedence
3.2.4 Fundamental Limits of Time Measurement
3.3 Dense Time Versus Sparse Time
3.3.1 Dense Time Base
3.3.2 Sparse Time Base
3.3.3 Space-Time Lattice
3.3.4 Cyclic Representation of Time
3.4 Internal Clock Synchronization
3.4.1 The Synchronization Condition
3.4.2 Central Master Synchronization
3.4.3 Fault-Tolerant Synchronization Algorithms
3.4.4 State Correction Versus Rate Correction
3.5 External Clock Synchronization
3.5.1 External Time Sources
3.5.2 Time Gateway
3.5.3 Time Formats
4 Real-Time (RT) Model
4.1 Model Outline
4.1.1 Components and Messages
4.1.2 Cluster of Components
4.1.3 Temporal Control Versus Logical Control
4.1.4 Event-Triggered Control Versus Time-Triggered Control
4.2 Component State
4.2.1 Definition of State
4.2.2 The Pocket Calculator Example
4.2.3 Ground State
4.2.4 Database Components
4.3 The Message Concept
4.3.1 Message Structure
4.3.2 Event Information Versus State Information
4.3.3 Event-Triggered (ET) Message
4.3.4 Time-Triggered (TT) Message
4.4 Component Interfaces
4.4.1 Interface Characterization
4.4.2 Linking Interface (LIF)
4.4.3 Technology-Independent Interface (TII)
4.4.4 Technology-Dependent Interface (TDI)
4.4.5 Local Interfaces
4.5 Gateway Component
4.5.1 Property Mismatches
4.5.2 LIF Versus Local Interface of a Gateway Component
4.5.3 Standardized Message Interface
4.6 Linking Interface Specification
4.6.1 Transport Specification
4.6.2 Operational Specification
4.6.3 Meta-Level Specification
4.7 Component Integration
4.7.1 Principles of Composability
4.7.2 Integration Viewpoints
4.7.3 System of Systems
5 Temporal Relations
5.1 Real-Time Entities
5.1.1 Sphere of Control
5.1.2 Discrete and Continuous Real-Time Entities
5.2 Observations
5.2.1 Untimed Observation
5.2.2 Indirect Observation
5.2.3 State Observation
5.2.4 Event Observation
5.3 Real-Time Images and Real-Time Objects
5.3.1 Real-Time Images
5.3.2 Real-Time Objects
5.4 Temporal Accuracy
5.4.1 Definition
5.4.2 Classification of Real-Time Images
5.4.3 State Estimation
5.4.4 Composability Considerations
5.5 Permanence and Idempotency
5.5.1 Permanence
5.5.2 Duration of the Action Delay
5.5.3 Accuracy Interval Versus Action Delay
5.5.4 Idempotency
5.6 Determinism
5.6.1 Definition of Determinism
5.6.2 Consistent Initial States
5.6.3 Nondeterministic Design Constructs (NDDCs)
5.6.4 Recovery of Determinism
6 Dependability
6.1 Basic Concepts
6.1.1 Faults
6.1.2 Errors
6.1.3 Failures
6.2 Information Security
6.2.1 Secure Information Flow
6.2.2 Security Threats
6.2.3 Cryptographic Methods
6.2.4 Network Authentication
6.2.5 Protection of Real-Time Control Data
6.3 Anomaly Detection
6.3.1 What Is an Anomaly?
6.3.2 Failure Detection
6.3.3 Error Detection
6.4 Fault Tolerance
6.4.1 Fault Hypotheses
6.4.2 Fault-Tolerant Unit
6.4.3 The Membership Service
6.5 Robustness and Resilience
6.5.1 The Concept of Robustness
6.5.2 The Concept of Resilience
6.6 Component Reintegration
6.6.1 Finding a Reintegration Point
6.6.2 Minimizing the Ground State
6.6.3 Component Restart
7 Real-Time Communication
7.1 Requirements
7.1.1 Timeliness
7.1.2 Dependability and Security
7.1.3 Flexibility
7.1.4 Communication Bandwidth and Cost Efficiency
7.2 Design Principles and Pitfalls
7.2.1 Real-Time Network Model
7.2.2 Message Types
7.2.3 Flow Control
7.2.4 Design Limitations
7.2.5 Design Pitfalls
7.3 Event-Triggered Communication
7.3.1 CAN
7.3.2 Ethernet
7.4 Rate-Constrained Communication
7.4.1 Avionics Full-Duplex Switched Ethernet (AFDX): ARINC664-p7
7.4.2 Audio/Video Bridging: IEEE 802.1 AVB
7.5 Time-Triggered Communication
7.5.1 TTP
7.5.2 TTEthernet
7.5.3 Time-Sensitive Networking: IEEE 802.1 TSN
8 Power and Energy Awareness
8.1 Power and Energy
8.1.1 Basic Concepts
8.1.2 Energy Estimation
8.1.3 Thermal Effects and Reliability
8.2 Hardware Power Reduction Techniques
8.2.1 Device Scaling
8.2.2 Low-Power Hardware Design
8.2.3 Voltage and Frequency Scaling
8.2.4 Sub-threshold Logic
8.3 System Architecture
8.3.1 Technology-Agnostic Design
8.3.2 Pollack's Rule
8.3.3 Power Gating
8.3.4 Real Time Versus Execution Time
8.4 Software Techniques
8.4.1 System Software
8.4.2 Application Software
8.4.3 Software Tools
9 Real-Time Operating Systems
9.1 Inter-Component Communication
9.1.1 Technology-Independent Interface (TII)
9.1.2 Linking Interface (LIF)
9.1.3 Technology-Dependent Interface (TDI)
9.1.4 Generic Middleware (GM)
9.2 Task Management
9.2.1 Simple Tasks
9.2.2 Trigger Tasks
9.2.3 Complex Tasks
9.3 The Dual Role of Time
9.3.1 Time as Data
9.3.2 Time as Control
9.4 Inter-Task Interactions
9.4.1 Coordinated Static Schedules
9.4.2 The Non-blocking Write (NBW) Protocol
9.4.3 Semaphore Operations
9.5 Process Input/Output
9.5.1 Analog Input/Output
9.5.2 Digital Input/Output
9.5.3 Interrupts
9.5.4 Fault-Tolerant Actuators
9.5.5 Intelligent Instrumentation
9.5.6 Physical Installation
9.6 Agreement Protocols
9.6.1 Raw Data, Measured Data, and Agreed Data
9.6.2 Syntactic Agreement
9.6.3 Semantic Agreement
9.7 Error Detection
9.7.1 Monitoring Task Execution Times
9.7.2 Monitoring Interrupts
9.7.3 Double Execution of Tasks
9.7.4 Watchdogs
10 Real-Time Scheduling
10.1 The Scheduling Problem
10.1.1 Classification of Scheduling Algorithms
10.1.2 Schedulability Test
10.1.3 The Adversary Argument
10.2 Worst-Case Execution Time
10.2.1 WCET of Simple Tasks
10.2.2 WCET of Complex Tasks
10.2.3 Anytime Algorithms
10.2.4 State of Practice
10.3 Static Scheduling
10.3.1 Static Scheduling Viewed as a Search
10.3.2 Increasing the Flexibility in Static Schedules
10.4 Dynamic Scheduling
10.4.1 Scheduling Independent Tasks
10.4.2 Scheduling Dependent Tasks
10.5 Alternative Scheduling Strategies
10.5.1 Scheduling in Distributed Systems
10.5.2 Feedback Scheduling
11 System Design
11.1 System Design
11.1.1 The Design Process
11.1.2 The Role of Constraints
11.1.3 System Design Versus Software Design
11.2 Design Phases
11.2.1 Purpose Analysis
11.2.2 Requirements Capture
11.2.3 Architecture Design
11.2.4 Design of Components
11.3 Design Styles
11.3.1 Model-Based Design
11.3.2 Component-Based Design
11.3.3 Architecture Design Languages
11.3.4 Test of a Decomposition
11.4 Design of Safety-Critical Systems
11.4.1 What Is Safety?
11.4.2 Safety Analysis
11.4.3 Safety Case
11.4.4 Safety Standards
11.5 Design Diversity
11.5.1 Diverse Software Versions
11.5.2 An Example of a Fail-Safe System
11.5.3 Multilevel System
11.6 Design for Maintainability
11.6.1 Cost of Maintenance
11.6.2 Maintenance Strategy
11.6.3 Software Maintenance
11.7 The Time-Triggered Architecture
11.7.1 Principle of a Consistent Global Time
11.7.2 Principle of Component Orientation
11.7.3 Principle of Coherent Communication
11.7.4 Principle of Fault Tolerance
12 Validation
12.1 Validation Versus Verification
12.2 Testing Challenges
12.2.1 Design for Testability
12.2.2 Test Data Selection
12.2.3 Test Oracle
12.2.4 System Evolution and Technology Readiness Levels (TRLs)
12.3 Testing of Component-Based Systems
12.3.1 Component Provider
12.3.2 Component User
12.3.3 Communicating Components
12.4 Formal Methods
12.4.1 Formal Methods in the Real World
12.4.2 Classification of Formal Methods
12.4.3 Benefits of Formal Methods
12.4.4 Model Checking
12.5 Fault Injection
12.5.1 Software-Implemented Fault Injection
12.5.2 Physical Fault Injection
12.5.3 Sensor and Actuator Failures
13 Internet of Things
13.1 The Vision of the Internet of Things (IoT)
13.2 Drivers for an IoT
13.2.1 Uniformity of Access
13.2.2 Logistics
13.2.3 Energy Savi ngs
13.2.4 Physical Security and Safety
13.2.5 Industrial
13.2.6 Medical
13.2.7 Lifestyle
13.3 Technical Issues of the IoT
13.3.1 Internet Integration
13.3.2 Naming and Identification
13.3.3 Near-Field Communication
13.3.4 IoT Device Capabilities Versus Cloud Computing
13.3.5 Autonomic Components
13.4 RFID Technology
13.4.1 Overview
13.4.2 The Electronic Product Code (EPC)
13.4.3 RFID Tags
13.4.4 RFID Readers
13.4.5 RFID Security
13.5 Wireless Sensor Networks (WSN)
14 Cloud and Fog Computing
14.1 Introduction
14.2 Characteristics of the Cloud
14.3 The Advent of Fog Computing
14.3.1 Fog Computing for Distributed Embedded Systems
14.3.2 Fog Computing Benefits and Risks
14.3.3 General Fog Computing and Comparison to Edge Computing
14.4 Selected Cloud and Fog Technologies
14.4.1 Resource Pooling
14.4.2 Connectivity
14.4.3 Configuration
14.4.4 System Design Automation
14.5 Example Use Cases
14.5.1 Cloud Computing-Enabled Use Cases
14.5.2 Fog Computing-Enabled Use Cases
14.5.3 Nerve
Annexes
References
Index