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RTOS (Real-Time Operating System)
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Real-Time Characteristics: The ability to respond to external events and execute tasks within a specified time frame, such as in industrial control, ensuring precise timing for sensor signal acquisition and actuator control operations, thereby maintaining the stable and efficient operation of automated production lines.
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Task Scheduling Mechanism: Understanding preemptive scheduling (where high-priority tasks can interrupt low-priority tasks to ensure timely processing of high-priority tasks) and non-preemptive scheduling (executing tasks in the order they are initiated, switching tasks only when a task voluntarily relinquishes CPU resources).
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Task Operations: Mastering operations such as creating, deleting, suspending, and resuming tasks to flexibly manage the task lifecycle and meet the needs of different stages of the system.
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Inter-Task Communication: Ensuring collaborative work between tasks through mechanisms such as semaphores (used for task synchronization and mutual exclusion, ensuring safe access to shared resources when multiple tasks are involved) and message queues (for data transmission between tasks, such as sending data collected by one task to another processing task via a message queue).
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Embedded Linux
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Application Advantages: Widely used in devices such as smart home devices and network routers that require cost-effectiveness and open-source solutions.
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Kernel Structure: Understanding process management (including process creation, destruction, scheduling, and the parent-child process relationship, such as optimizing process management and scheduling in multi-service embedded network servers to enhance concurrent processing capabilities), memory management (mastering the concept of virtual memory, memory allocation and recycling mechanisms to improve memory usage efficiency), and device driver frameworks.
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Device Driver Development: Mastering development methods for different types of device drivers, including character devices (such as keyboards and mice for simple device driver development to implement data read/write), block devices (such as hard drives for block data read/write and management), and network devices (such as Ethernet controllers for data network transmission), enabling hardware devices to work in coordination with the operating system.
System Boot and Initialization
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Overview of the Boot Process: The system starts from power-on, initializes through the BIOS (Basic Input/Output System) or BootLoader, loads the operating system kernel, and hands over control.
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BootLoader: A small program that runs before the operating system kernel, functioning similarly to a PC’s BIOS, responsible for hardware initialization (such as initializing the CPU clock, memory controller, and other critical hardware) and loading the kernel. Different embedded platforms have different BootLoader programs, such as u-Boot for ARM platforms. Mastering its principles and configuration methods is beneficial for troubleshooting and custom development when boot issues arise in embedded devices.