📚 Hardware | 硬件
Hardware forms the physical foundation of every computing device, from smartphones and laptops to supercomputers and embedded controllers. Understanding its components and how they interact is essential for anyone studying computer science, as it reveals how machines execute instructions, store information, and communicate with the outside world.
硬件构成了每台计算设备的物理基础，从智能手机、笔记本电脑到超级计算机和嵌入式控制器。了解其组件及它们如何互动，对于学习计算机科学的人来说至关重要，因为它揭示了机器如何执行指令、存储信息以及与外部世界通信。
This article breaks down the key hardware topics covered in the Cambridge IGCSE Computer Science syllabus, pairing English explanations with their Chinese equivalents to support bilingual learners. You will explore the central processor, memory, storage, input/output peripherals, and the system architecture that ties everything together.
本文将拆解剑桥 IGCSE 计算机科学大纲中涵盖的关键硬件主题，将英文解释与中文配对，以支持双语学习者。你将探索中央处理器、内存、存储、输入/输出外设，以及将所有部件连接在一起的系统架构。
1. What is Hardware? | 什么是硬件？
Hardware refers to the physical parts of a computer system—the components you can see and touch. This includes internal devices such as the CPU, RAM, and hard drive, as well as external peripherals like keyboards, mice, and monitors.
硬件指的是计算机系统的物理部分——你可以看到和触摸的组件。这包括内部设备，如 CPU、RAM 和硬盘，以及外部外设，如键盘、鼠标和显示器。
Hardware is distinct from software, which consists of the programs and data that instruct the hardware. Without hardware, software has no platform to run on; without software, hardware is just inert electronics.
硬件与软件不同，软件由指示硬件的程序和数据组成。没有硬件，软件就没有运行平台；没有软件，硬件只是无生命的电子元件。
2. Central Processing Unit (CPU) | 中央处理器 (CPU)
The CPU, often called the processor, is the brain of the computer. It executes program instructions by performing calculations, making logical decisions, and controlling the flow of data. Modern CPUs contain one or more cores, each capable of processing instructions independently.
CPU 通常被称为处理器，是计算机的大脑。它通过执行计算、做出逻辑决策和控制数据流来执行程序指令。现代 CPU 包含一个或多个核心，每个核心都能独立处理指令。
Inside the CPU, the arithmetic logic unit (ALU) handles mathematical and logical operations, while the control unit (CU) directs the operation of the processor by sending control signals. Registers are small, high-speed storage locations that hold data and instructions currently being processed.
在 CPU 内部，算术逻辑单元 (ALU) 处理数学和逻辑运算，而控制单元 (CU) 通过发送控制信号来指导处理器的操作。寄存器是小而高速的存储位置，用于保存当前正在处理的数据和指令。
Clock speed, measured in gigahertz (GHz), indicates how many cycles a CPU can execute per second. A higher clock speed generally means faster performance, but other factors like architecture and number of cores also matter.
时钟速度以吉赫兹 (GHz) 为单位，表示 CPU 每秒可以执行多少个周期。更高的时钟速度通常意味着更快的性能，但架构和核心数量等其他因素也很重要。
3. The Fetch-Decode-Execute Cycle | 取指-解码-执行周期
At the heart of every CPU is a continuous loop known as the fetch-decode-execute cycle. In the fetch stage, the processor retrieves an instruction from memory. In the decode stage, the control unit interprets what the instruction means. In the execute stage, the CPU carries out the required operation, often using the ALU.
每个 CPU 的核心都是一个称为取指-解码-执行周期的连续循环。在取指阶段，处理器从内存中检索一条指令。在解码阶段，控制单元解读指令的含义。在执行阶段，CPU 执行所需的操作，通常使用 ALU。
After execution, the cycle repeats with the next instruction unless a jump or branch instruction changes the flow. This simple three-step process is the foundation of all program execution.
执行后，周期会重复执行下一条指令，除非跳转或分支指令改变了流程。这个简单的三步过程是所有程序执行的基础。
4. Memory: RAM and ROM | 内存：RAM 和 ROM
Random Access Memory (RAM) is volatile, meaning it loses its contents when power is turned off. RAM temporarily holds the operating system, applications, and data that the CPU is actively using. More RAM allows a computer to run more programs simultaneously without slowing down.
随机存取存储器 (RAM) 是易失性的，意味着断电后会丢失内容。RAM 临时保存 CPU 正在使用的操作系统、应用程序和数据。更多的 RAM 可以让计算机同时运行更多程序而不减慢速度。
Read Only Memory (ROM) is non‑volatile and stores the firmware or BIOS—the essential instructions needed to start the computer. ROM retains its data even without power, making it ideal for boot routines and embedded control programs.
只读存储器 (ROM) 是非易失性的，存储固件或 BIOS——启动计算机所需的基本指令。ROM 即使在没有电源的情况下也能保留数据，这使其非常适合启动程序和嵌入式控制程序。
5. Storage Devices | 存储设备
Storage devices retain data permanently, unlike RAM. The main types used today include Hard Disk Drives (HDD), Solid State Drives (SSD), and flash drives. Each type differs in speed, capacity, and physical construction.
与 RAM 不同，存储设备永久保存数据。当今使用的主要类型包括硬盘驱动器 (HDD)、固态驱动器 (SSD) 和闪存驱动器。每种类型在速度、容量和物理结构上有所不同。
| Device | Typical capacity | Read / write speed | Moving parts? |
|---|---|---|---|
| HDD | 500 GB – 4 TB | 80–160 MB/s | Yes |
| SSD | 120 GB – 2 TB | 200–550 MB/s | No |
| USB flash drive | 8 GB – 256 GB | 10–40 MB/s | No |
SSDs are faster and more shock‑resistant than HDDs because they use flash memory with no mechanical parts. Optical discs such as CDs and DVDs are older storage media still used for archival purposes or software distribution.
SSD 比 HDD 更快、更抗震，因为它们使用没有机械部件的闪存。CD 和 DVD 等光盘是较旧的存储介质，仍用于存档或软件分发。
6. Input Devices | 输入设备
Input devices allow users to send data and control signals to a computer. Common examples include keyboards for text entry, mice and touchpads for pointing, touchscreens for direct manipulation, and microphones for audio input.
输入设备允许用户将数据和控制信号发送到计算机。常见的例子包括用于文本输入的键盘、用于指向的鼠标和触摸板、用于直接操作的触摸屏，以及用于音频输入的麦克风。
Sensors such as accelerometers, light sensors, and temperature probes act as input devices in embedded systems, gathering real‑world data for processing. The variety of input devices reflects the many ways humans and environments interact with computers.
加速度计、光传感器和温度探头等传感器在嵌入式系统中充当输入设备，收集现实世界的数据以供处理。输入设备的多样性反映了人类和环境与计算机交互的多种方式。
7. Output Devices | 输出设备
Output devices convert processed data back into a human‑perceptible form. Monitors and projectors display visual information, while printers produce hard copies of documents and images. Speakers and headphones output audio signals.
输出设备将处理后的数据转换回人类可感知的形式。显示器和投影仪显示视觉信息，而打印机生成文档和图像的硬拷贝。扬声器和耳机输出音频信号。
Some devices, such as actuators and motors, produce mechanical motion, allowing computers to control physical systems. A robot arm in a factory receives output signals that command its movements based on processed sensor data.
某些设备，如执行器和电机，产生机械运动，使计算机能够控制物理系统。工厂中的机器人手臂接收输出信号，这些信号根据处理后的传感器数据命令其移动。
8. Motherboard and System Buses | 主板与系统总线
The motherboard is the main printed circuit board that connects all hardware components. It provides sockets for the CPU, RAM slots, expansion slots, and connectors for storage and peripheral devices.
主板是连接所有硬件组件的主印刷电路板。它提供 CPU 插槽、RAM 插槽、扩展槽以及存储和外设的连接器。
Data travels between components along sets of parallel wires called buses. The three essential buses are the address bus (carries memory addresses), the data bus (carries the actual data), and the control bus (sends timing and command signals). Together they form the backbone of the system’s communication.
数据通过称为总线的并行线路在组件之间传输。三种基本总线是地址总线（传送内存地址）、数据总线（传送实际数据）和控制总线（发送时序和命令信号）。它们共同构成了系统通信的骨干。
9. Graphics and Sound Cards | 显卡和声卡
A graphics card (or GPU – graphics processing unit) is a dedicated processor for rendering images, video, and animations. It has its own video memory (VRAM) and accelerates 3D rendering, freeing the main CPU for other tasks.
显卡（或 GPU——图形处理单元）是用于渲染图像、视频和动画的专用处理器。它拥有自己的视频内存 (VRAM)，并加速 3D 渲染，使主 CPU 可以处理其他任务。
Sound cards convert digital audio data into analogue signals that can be played through speakers or headphones. Modern motherboards often integrate both graphics and sound capabilities, reducing the need for separate expansion cards.
声卡将数字音频数据转换为可以通过扬声器或耳机播放的模拟信号。现代主板通常集成图形和声音功能，减少了对独立扩展卡的需求。
10. Power Supply and Cooling | 电源与散热
The power supply unit (PSU) converts alternating current (AC) from the wall outlet into low‑voltage direct current (DC) that the computer components require. It distributes power at different voltages (e.g., +3.3 V, +5 V, +12 V) to various parts of the system.
电源单元 (PSU) 将来自墙上插座的交流电 (AC) 转换为计算机组件所需的低压直流电 (DC)。它按不同电压（例如 +3.3 V、+5 V、+12 V）将电力分配到系统的各个部分。
Heat is a by‑product of electrical operation, and excessive heat can damage components. Cooling solutions include heat sinks, which dissipate heat passively, and fans that actively move hot air away. High‑performance systems may use liquid cooling for greater efficiency.
热量是电气操作的副产品，过热会损坏组件。散热解决方案包括被动散热的散热器和主动将热空气带走的风扇。高性能系统可能使用液冷以获得更高的效率。
11. Embedded Systems | 嵌入式系统
An embedded system is a computer built into a larger device to perform a dedicated function. Unlike general‑purpose computers, embedded systems run fixed software stored in ROM and often lack a full operating system. Examples include microwave ovens, washing machines, traffic lights, and car engine controllers.
嵌入式系统是内置于更大设备中以执行特定功能的计算机。与通用计算机不同，嵌入式系统运行存储在 ROM 中的固定软件，通常没有完整的操作系统。例子包括微波炉、洗衣机、交通灯和汽车发动机控制器。
These systems are designed for low power consumption, high reliability, and real‑time responses. Their hardware is highly optimised for the specific task, making them cost‑effective for mass production.
这些系统设计为低功耗、高可靠性和实时响应。它们的硬件针对特定任务进行了高度优化，使之在大规模生产中具有成本效益。
12. Comparing Hardware Specifications | 比较硬件规格
When evaluating a computer's performance, several specifications must be considered together. Key metrics include CPU clock speed and core count, amount of RAM, storage type and capacity, and the capabilities of the graphics system.
在评估计算机性能时，必须同时考虑多个规格。关键指标包括 CPU 时钟速度和核心数量、RAM 大小、存储类型和容量，以及图形系统的能力。
A system with a fast processor but insufficient RAM may still feel sluggish because the operating system is forced to use slower virtual memory. Similarly, an SSD can dramatically improve boot and load times compared to an HDD, even on an older CPU.
一个拥有快速处理器但 RAM 不足的系统可能仍然感觉迟缓，因为操作系统被迫使用较慢的虚拟内存。同样，与 HDD 相比，SSD 可以显著改善启动和加载时间，即使在较旧的 CPU 上也是如此。
Understanding these relationships helps users choose the right hardware for their needs, whether for gaming, office work, or scientific computing.
了解这些关系有助于用户根据自己的需求选择合适的硬件，无论用于游戏、办公还是科学计算。
Published by TutorHao | Computer Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图