I. Embedded Systems
An embedded system is a specialized computer system that is application-centric, based on modern computer technology, and capable of flexibly tailoring software and hardware modules according to user needs (function, reliability, cost, size, power consumption, environment, etc.).
Key points summary:
Application-centric: This emphasizes that the goal of embedded systems is to meet specific user needs. For the vast majority of complete embedded systems, users can directly enjoy their functionality simply by turning on the power, requiring no secondary development or only minimal configuration.
Specialization: Embedded systems are mostly used in applications that have high requirements for reliability and real-time performance. This determines that dedicated systems serving specific applications are the mainstream model for embedded systems, which does not emphasize the system's versatility and scalability. This specialization usually also leads to embedded systems being a final system with tightly integrated hardware and software, as this is the only way to more effectively improve the overall system reliability, reduce costs, and provide a better user experience.
With modern computer technology at its core, the most basic supporting technologies for embedded systems generally include integrated circuit design technology, system architecture technology, sensing and detection technology, embedded operating system and real-time operating system technology, high-reliability software development technology for resource-constrained systems, system formal specification and verification technology, communication technology, low-power technology, data analysis, signal processing and control optimization technology for specific application areas, etc. These technologies, based on the basic principles of computers, are integrated into specific dedicated devices to form an embedded system.
Hardware and software can be customized: Embedded systems are used in a wide variety of applications, which bring about very different design requirements (functionality, performance, reliability, cost, power consumption). As a result, it is difficult to find a single solution that can meet all system requirements. Therefore, it is an inevitable technical route for the development of embedded technology to flexibly customize hardware and software and build a final system that meets the requirements according to different needs.
II. Common Applications of Embedded Operating Systems
Embedded operating systems have a variety of uses, including:
Automated Teller Machines (ATMs). An ATM has a basic operating system that allows the machine to read a user's debit card and personal identification number input and perform banking account functions such as withdrawals or balance inquiries. The operating system does nothing more than respond to user input and communicate with the ATM hardware.
Mobile phones. Mobile phones require an operating system such as Android or iOS to boot up the phone and enable applications to communicate with other mobile phone hardware.
Electric vehicles. The microcontroller hosts an embedded operating system that processes functions such as braking or pressure sensing. For example, a certain amount of pressure on the front bumper might cause an airbag to deploy. This type of function is called reactive operation because it reacts to input.
Industrial control systems. Sensors are used in industrial control systems to measure factory conditions and send alerts when they become dangerous. Sensors contain an embedded operating system that enables them to perform these tasks.
Traffic lights. An embedded operating system enables traffic lights to cycle through different signals at programmed time intervals.
Basic Input/Output System. In some cases, the BIOS can be considered an embedded operating system because it is the firmware that enables more complex operating systems on desktop computers to interact with computer hardware.
Embedded systems consist of hardware components, and embedded operating systems organize these hardware components to perform tasks for larger devices.
Types of Embedded Operating Systems
Embedded operating systems are designed specifically for the tasks they will perform. Various types of operating systems include:
A multitasking operating system can execute multiple tasks simultaneously. It uses job scheduling to perform basic tasks. For example, a mobile phone operating system allocates CPU resources among multiple tasks.
Real-time operating systems (RTOS) are designed to be reactive. They process input as it is received and respond within a specific time frame. If the response time exceeds the specified time period, the system may fail. ROS sometimes use rate-monotonic scheduling, which assigns priorities to tasks.
Single-loop control systems. This type of embedded operating system controls a single variable. An example is temperature control in a smart home. A smart thermostat measures the temperature inside the house and shuts off the heating if it exceeds a user-set limit.
