Real-Time Embedded Systems
Open-Source Operating Systems Perspective
Preview
Book Description
From the Foreword:
"…the presentation of real-time scheduling is probably the best in terms of clarity I have ever read in the professional literature. Easy to understand, which is important for busy professionals keen to acquire (or refresh) new knowledge without being bogged down in a convoluted narrative and an excessive detail overload. The authors managed to largely avoid theoretical-only presentation of the subject, which frequently affects books on operating systems.
… an indispensable [resource] to gain a thorough understanding of the real-time systems from the operating systems perspective, and to stay up to date with the recent trends and actual developments of the open-source real-time operating systems."
—Richard Zurawski, ISA Group, San Francisco, California, USA
Real-time embedded systems are integral to the global technological and social space, but references still rarely offer professionals the sufficient mix of theory and practical examples required to meet intensive economic, safety, and other demands on system development. Similarly, instructors have lacked a resource to help students fully understand the field. The information was out there, though often at the abstract level, fragmented and scattered throughout literature from different engineering disciplines and computing sciences.
Accounting for readers’ varying practical needs and experience levels, Real Time Embedded Systems: Open-Source Operating Systems Perspective offers a holistic overview from the operating-systems perspective. It provides a long-awaited reference on real-time operating systems and their almost boundless application potential in the embedded system domain.
Balancing the already abundant coverage of operating systems with the largely ignored real-time aspects, or "physicality," the authors analyze several realistic case studies to introduce vital theoretical material. They also discuss popular open-source operating systems—Linux and FreRTOS, in particular—to help embedded-system designers identify the benefits and weaknesses in deciding whether or not to adopt more traditional, less powerful, techniques for a project.
Table of Contents
Introduction
I: Concurrent Programming Concepts
A Case Study: Vision Control
Input Output on Computers
Input/Output Operations and the Operating System
Acquiring Images froma Camera Device
Edge Detection
Finding the Center Coordinates of a Circular Shape
Real-Time Concurrent Programming Principles
The Role of Parallelism
Definition of Process
Process State
Process Life Cycle and Process State Diagram
Multithreading
Deadlock
A Simple Example
Formal Definition of Deadlock
Reasoning about Deadlock: The Resource Allocation Graph
Living with Deadlock
Deadlock Prevention
Deadlock Avoidance
Deadlock Detection and Recovery
Interprocess Communication Based on Shared Variables
Race Conditions and Critical Regions
Hardware-Assisted Lock Variables
Software-Based Mutual Exclusion
From Active to Passive Wait
Semaphores
Monitors
Interprocess Communication Based on Message Passing
Basics ofMessage Passing
Naming Scheme
Synchronization Model
Message Buffers
Message Structure and Contents
Producer–Consumer Problem with Message Passing
Interprocess Communication Primitives in POSIX/Linux
Threads and Processes
Interprocess Communication among Threads
Interprocess Communication among Processes
Clocks and Timers
Threads or Processes?
Interprocess Communication Primitives in FreeRTOS
FreeRTOS Threads and Processes
Message Queues
Counting, Binary, and Mutual Exclusion Semaphores
Clocks and Timers
Network Communication
The Ethernet Protocol
TCP/IP and UDP
Sockets
UDP Sockets
Lock and Wait-Free Communication
Basic Principles and Definitions
Multidigit Registers
Application to the Readers/Writer Problem
Universal Constructions
II: Real-Time Scheduling Analysis
Real-Time Scheduling Based on the Cyclic Executive
Scheduling and Process Models
The Cyclic Executive
Choice of Major and Minor Cycle Length
Tasks with Large Period or Execution Time
Real-Time, Task-Based Scheduling
Fixed and Variable Task Priority
Rate Monotonic
The EarliestDeadline First Scheduler
Schedulability Analysis Based on Utilization
Processor Utilization
Sufficient Schedulability Test for Rate Monotonic
Schedulability Test for EDF
Schedulability Analysis Based on Response Time Analysis
Response Time Analysis
Computing the Worst-Case Execution Time
Aperiodic and Sporadic Tasks
Task Interactions and Blocking
The Priority Inversion Problem
The Priority Inheritance Protocol
The Priority Ceiling Protocol
Schedulability Analysis and Examples
Self-Suspension and Schedulability Analysis
Self-Suspension and the Critical Instant Theorem
Self-Suspension and Task Interaction
Extension of the Response Time Analysis Method
III: Advanced Topics
Internal Structure of FreeRTOS
Task Scheduler/Context Switch
Synchronization Primitives
Porting FreeRTOS to a New Architecture
Internal Structures and Operating Principles of Linux Real-Time Extensions
The Linux Scheduler
Kernel Preemption
The PREEMPT RT Linux Patch
The Dual-Kernel Approach
OS Abstraction Layer
An Object Oriented Interface to Threads and Other IPC Mechanisms
A Sample Multiplatform Application
Control Theory and Digital Signal Processing Primer
Case Study 1: Controlling the Liquid Level in a Tank
Case Study 2: Implementing a Digital Low-Pass Filter