📚 Year 9 SQA Computing: Quick Memory Guide to Key Terms | Year 9 SQA 计算机：核心术语速记指南
This guide presents essential computing vocabulary for Year 9 students following the SQA curriculum. Mastering these terms will boost your confidence in exams and practical tasks, because SQA questions almost always reward precise definitions rather than vague descriptions. Every section below pairs the English term with its Chinese meaning, adds the detail an examiner expects, and finishes with a memory hook so the word sticks.
本指南为遵循 SQA 课程的 Year 9 学生整理了必备的计算机术语。掌握这些术语将提升你在考试和实践任务中的信心，因为 SQA 的题目通常奖励精确的定义，而不是模糊的描述。下文每一节都把英文术语与中文含义配对，补充考官期待的细节，并在最后给出记忆钩子，帮助你真正记住这些词。
1. Why Key Terms Matter | 为什么核心术语如此重要
Computing is a subject built on vocabulary. A question that asks you to 'describe the purpose of RAM' cannot be answered with a story about your laptop being slow; it needs the words volatile, temporary, and currently in use. Short, accurate sentences score more marks than long, emotional ones.
计算机是一门建立在术语之上的学科。如果题目问 "描述 RAM 的作用"，你不能用"我的笔记本很卡"这种故事来回答，而必须用到"易失性""临时""当前正在使用"这些词。简短而准确的句子，比冗长而感性的句子得分更高。
The SQA course also builds vertically. Year 9 vocabulary becomes National 5 content, and National 5 content becomes Higher content. A term you learn now, such as 'protocol' or 'primary key', will reappear for the next four years. Learning it once properly saves you time later.
SQA 课程是纵向递进的。Year 9 的术语会成为 National 5 的内容，National 5 的内容又会成为 Higher 的内容。你现在学的"协议"或"主键"这类词，未来四年还会反复出现。一次学扎实，后面就省时间。
- Command words – State, describe, explain, compare and evaluate each demand a different depth of answer. | 指令词 – "陈述""描述""解释""比较"和"评价"要求的答题深度各不相同。
- Mark allocation – One mark usually equals one clearly made point, so write separate sentences rather than one long one. | 分值分配 – 通常一分对应一个清晰的观点，因此要分成独立句子，而不是写成一个长句。
- Technical accuracy – Wrong terminology loses marks even when the idea behind it is correct. | 技术准确性 – 即使想法正确，术语用错也会失分。
A useful habit is to keep a two-column glossary: term on the left, your own definition plus one real example on the right. Rewriting a definition in your own words is far more effective than copying it out, because your brain has to process the meaning rather than just the letters.
一个有用的习惯是准备一个两栏词汇表：左边写术语，右边写你自己的定义加一个真实例子。用自己的话重写定义，比抄写定义有效得多，因为大脑必须处理含义，而不只是字母。
2. Hardware Basics: CPU, RAM and ROM | 硬件基础：CPU、RAM 与 ROM
Central Processing Unit (CPU) – The 'brain' of the computer that carries out instructions and processes data. It fetches an instruction from memory, decodes what it means, executes it, and stores the result, a cycle repeated billions of times per second.
中央处理器 (CPU) – 计算机的"大脑"，负责执行指令和处理数据。它从内存中取指令、译码、执行并保存结果，这个循环每秒重复数十亿次。
Inside the CPU, the control unit directs the flow of data, the Arithmetic Logic Unit (ALU) performs calculations and logical comparisons, and registers hold the tiny amounts of data being worked on right now. Clock speed, measured in gigahertz (GHz), shows how many cycles happen per second, while the number of cores shows how many instructions can be handled at once.
在 CPU 内部，控制单元指挥数据流动，算术逻辑单元（ALU）执行计算和逻辑比较，寄存器则保存当前正在处理的一小部分数据。时钟频率以吉赫兹（GHz）为单位，表示每秒发生的周期数；核心数量则表示可以同时处理多少条指令。
Random Access Memory (RAM) – Volatile memory that temporarily stores data and programs currently in use. 'Volatile' means the contents are lost when the power is switched off, which is exactly why unsaved work disappears in a power cut.
随机存取存储器 (RAM) – 易失性存储器，临时存放当前使用的数据和程序。"易失性"意味着断电后内容会丢失，这正是停电时未保存的工作会消失的原因。
Read-Only Memory (ROM) – Non-volatile memory that stores instructions needed to boot the computer, such as the BIOS. Its contents are permanent and cannot normally be changed by the user.
只读存储器 (ROM) – 非易失性存储器，存放启动计算机所需的指令，例如 BIOS。其内容是永久性的，用户通常无法更改。
| Feature | 特性 | RAM | 随机存取存储器 | ROM | 只读存储器 |
| Volatility | 易失性 | Volatile – lost when power off | 易失 – 断电即丢失 | Non-volatile – kept when power off | 非易失 – 断电仍保留 |
| Contents | 内容 | Programs and data in use | 正在使用的程序和数据 | Start-up instructions (BIOS) | 启动指令（BIOS） |
| Writable? | 可写吗 | Yes, constantly | 可以，且不断读写 | No, read-only in normal use | 不可以，正常使用中只读 |
| Size | 容量 | Usually much larger | 通常大得多 | Usually small | 通常较小 |
Memory hook: RAM is your desk, ROM is the printed instruction card taped to it, and the CPU is you doing the work. A bigger desk lets you spread out more work at once, but nothing on the desk survives the night.
记忆钩子：RAM 是你的书桌，ROM 是贴在桌上的印刷说明卡，CPU 就是干活的你。桌子越大，一次能摊开的活儿越多，但桌上的东西过夜就没了。
3. Storage Devices and the Motherboard | 存储设备与主板
Storage (HDD & SSD) – Devices used to save files permanently; HDD uses magnetic platters, while SSD uses flash memory for faster access.
存储器 (HDD 和 SSD) – 用于永久保存文件的设备；HDD 使用磁性碟片，SSD 使用闪存以更快地进行访问。
A hard disk drive has spinning platters and a moving read/write head, so it is mechanical, cheaper per gigabyte, and vulnerable to being knocked while running. A solid state drive has no moving parts, so it is silent, more robust and much faster, but usually costs more for the same capacity.
硬盘驱动器（HDD）有旋转的碟片和移动的读写磁头，属于机械结构，每 GB 价格更便宜，但运行中受撞击容易损坏。固态硬盘（SSD）没有活动部件，因而安静、抗摔且速度快得多，但相同容量下通常更贵。
Motherboard – The main circuit board connecting all components of a computer. It carries the CPU socket, the RAM slots, expansion slots for graphics or network cards, and the buses that carry data between them.
主板 – 连接计算机所有组件的主电路板。它承载 CPU 插槽、内存插槽、显卡或网卡用的扩展槽，以及在各部件之间传输数据的总线。
- Secondary storage – Keeps data when the power is off; examples include HDD, SSD, USB flash drive, SD card and optical disc. | 辅助存储 – 断电后仍保存数据；例如 HDD、SSD、U 盘、SD 卡和光盘。
- Primary storage – RAM and ROM inside the computer, directly accessible by the CPU. | 主存储 – 计算机内部的 RAM 和 ROM，CPU 可直接访问。
- Capacity units – or 1; 8 bits = 1 byte; 1024 bytes = 1 KB; 1024 KB = 1 MB; 1024 MB = 1 GB; 1024 GB = 1 TB. | 容量单位 – 1 位是一个 0 或 1；8 位 = 1 字节；1024 字节 = 1 KB；1024 KB = 1 MB；1024 MB = 1 GB；1024 GB = 1 TB。
A classic exam trap is confusing memory with storage. Memory (RAM) is temporary and lost at shutdown; storage is permanent and survives. If a question says 'the computer forgets everything when switched off', it is asking about RAM, not about the SSD.
经典考试陷阱是把"内存"和"存储"搞混。内存（RAM）是临时的，关机即丢失；存储是永久的，会保留下来。如果题目说"计算机关机后忘掉一切"，它问的是 RAM，而不是 SSD。
4. Input and Output Devices | 输入与输出设备
Input Devices – Hardware that sends data into the computer (e.g., keyboard, mouse, scanner). Each device suits a particular job: a keyboard for text, a mouse for pointing, a scanner for turning paper documents into digital images.
输入设备 – 将数据输入计算机的硬件（例如键盘、鼠标、扫描仪）。每种设备适合特定任务：键盘用于文本，鼠标用于指向，扫描仪把纸质文档转成数字图像。
Output Devices – Hardware that presents data from the computer to the user (e.g., monitor, printer, speakers). Output can be visual, printed or audible, and the right choice depends on the audience and the situation.
输出设备 – 将计算机中的数据呈现给用户的硬件（例如显示器、打印机、扬声器）。输出可以是视觉的、打印的或声音的，选择哪种取决于受众和场景。
- Sensors – Input devices that measure physical quantities such as temperature, light, pressure or motion, often feeding automatic systems. | 传感器 – 测量温度、光照、压力或运动等物理量的输入设备，常为自动系统提供数据。
- Actuators – Output devices that cause a physical change, such as a motor turning or a valve opening. | 执行器 – 引起物理变化的输出设备，例如电机转动或阀门开启。
- Touchscreen – Both input and output, because it displays information and accepts touch at the same time. | 触摸屏 – 既是输入也是输出，因为它同时显示信息并接受触摸。
- Printer types – Inkjet is cheap and good for photos; laser is fast and cheap per page for bulk text; 3D printers produce physical objects. | 打印机类型 – 喷墨便宜且适合照片；激光速度快、大批量文本单页成本低；3D 打印机产出实体物件。
| Device | 设备 | Type | 类型 | Best used when | 最适用场景 |
| Keyboard | 键盘 | Input | 输入 | Large amounts of text | 大量文本输入 |
| Scanner | 扫描仪 | Input | 输入 | Digitising paper documents | 将纸质文档数字化 |
| Monitor | 显示器 | Output | 输出 | On-screen work and video | 屏幕作业与视频 |
| Speaker | 扬声器 | Output | 输出 | Audio feedback or music | 音频反馈或音乐 |
When an exam asks you to 'justify' a device choice, never say 'because it is good'. Say what the device does and why that suits the task: 'A laser printer is suitable because it produces high volumes quickly at a low cost per page.'
当考试要求你"论证"设备选择时，千万不要说"因为它好"。要说明该设备做什么，以及为什么适合这项任务："激光打印机适合，因为它能以较低的单页成本快速大量打印。"
5. Software and Operating Systems | 软件与操作系统
Software is the set of instructions that tells hardware what to do. It splits into system software, which runs the machine, and application software, which does the job the user actually wants, such as writing an essay or editing a photo.
软件是告诉硬件做什么的指令集合。它分为系统软件（维持机器运行）和应用软件（完成用户真正想做的事，例如写文章或修照片）。
An operating system is the most important piece of system software. It manages memory so programs do not overwrite each other, manages files and folders, schedules the CPU between tasks, provides the user interface, handles security and user accounts, and communicates with hardware through drivers.
操作系统是最重要的系统软件。它管理内存以防程序互相覆盖，管理文件和文件夹，在任务之间调度 CPU，提供用户界面，处理安全与用户账户，并通过驱动程序与硬件通信。
- Graphical user interface (GUI) – Windows, icons, menus and pointers; easy for beginners. | 图形用户界面 (GUI) – 窗口、图标、菜单和指针；对新手友好。
- Command line interface (CLI) – Text commands typed in; faster and more powerful for experts but harder to learn. | 命令行界面 (CLI) – 输入文字命令；对专家更快更强，但学习门槛高。
- Utility software – Small tools such as antivirus, backup, disk defragmenter and compression programs that keep the system healthy. | 实用工具软件 – 杀毒、备份、磁盘碎片整理和压缩程序等小型工具，用于维护系统健康。
- Open source vs proprietary – Open source code can be viewed and modified by anyone; proprietary code belongs to a company and is usually licensed for a fee. | 开源与专有 – 开源代码任何人都能查看和修改；专有代码属于公司，通常需付费授权。
Memory hook: hardware is the body, the operating system is the nervous system, and application software is whatever sport you decide to play that day.
记忆钩子：硬件是身体，操作系统是神经系统，应用软件则是你当天决定去做的运动。
6. Binary, Data Representation and Units | 二进制、数据表示与单位
Computers store everything as binary, using only 0 and 1, because a transistor has two reliable states: off and on. Denary (base 10) is what humans use, binary (base 2) is what the machine uses, and hexadecimal (base 16) is a convenient shorthand for programmers because one hex digit equals exactly four bits.
计算机把所有内容都存为二进制，只用 0 和 1，因为晶体管只有两个可靠状态：断开和接通。十进制（基 10）是人类使用的，二进制（基 2）是机器使用的，十六进制（基 16）则是程序员的便捷简写，因为一个十六进制位正好等于四位。
To convert denary to binary, repeatedly divide by 2 and read the remainders upwards. To convert 8-bit binary to denary, add the place values where a 1 appears, working from 128 down to 1.
将十进制转为二进制，可以不断除以 2，然后把余数从下往上读。将 8 位二进制转为十进制，则把出现 1 的位置对应的位值相加，从 128 依次降到 1。
8-bit place values: 128 64 32 16 8 4 2 1
8 位位值：128 64 32 16 8 4 2 1
Characters are stored using standards such as ASCII, which uses 7 or 8 bits per character, and Unicode, which uses more bits so it can represent every writing system, including Chinese characters and emoji.
字符使用 ASCII 等标准存储，每个字符用 7 或 8 位；Unicode 使用更多位，因此能表示世界上所有书写系统，包括汉字和表情符号。
A bitmap graphic stores an image as a grid of pixels. Its file size in bits depends on width, height and colour depth, where colour depth is the number of bits used to store each pixel's colour.
位图把图像存成像素网格。它的大小（以位计）取决于宽度、高度和颜色深度，其中颜色深度是存储每个像素颜色所用的位数。
File size (bits) = Width × Height × Colour depth
文件大小（位）= 宽 × 高 × 颜色深度
Sound is stored by sampling: the analogue wave is measured at regular intervals. Sample rate is how many measurements per second (in Hz), and sample resolution is the number of bits per measurement. Higher values mean better quality and a larger file.
声音通过采样存储：以固定间隔测量模拟波形。采样率是每秒的测量次数（单位 Hz），采样精度是每次测量的位数。数值越高，音质越好，文件也越大。
- Bit – a single binary digit, 0 or 1. | 位 – 单个二进制数字，0 或 1。
- Byte – 8 bits; enough for one ASCII character. | 字节 – 8 位；足以存放一个 ASCII 字符。
- Data vs information – data is raw facts and figures; information is data processed into something meaningful. | 数据与信息 – 数据是原始的事实和数字；信息是经过处理、具有意义的数据。
7. Networks and the Internet | 网络与互联网
A network is two or more devices connected so they can share data and resources. A local area network (LAN) covers one site such as a school, while a wide area network (WAN) spans cities or countries and usually relies on leased lines. The internet itself is the largest WAN of all.
网络是两个或更多设备连接起来共享数据和资源的系统。局域网（LAN）覆盖一个场所，例如一所学校；广域网（WAN）跨越城市或国家，通常依赖租用线路。互联网本身就是最大的广域网。
In a client-server network, powerful servers provide services such as file storage, user login and printing, which makes central management and backup easy. In a peer-to-peer network, each device shares directly with the others, which is cheaper and simple to set up but harder to secure and back up.
在客户端–服务器网络中，性能强大的服务器提供文件存储、用户登录和打印等服务，便于集中管理和备份。在对等网络中，每台设备直接与其他设备共享，成本更低、搭建简单，但安全和备份更难保障。
- Network interface card (NIC) – Hardware that allows a device to join a network. | 网卡 (NIC) – 让设备接入网络的硬件。
- Switch – Connects devices inside one LAN and forwards data only to the intended device. | 交换机 – 连接同一局域网内的设备，只把数据转发给目标设备。
- Router – Joins networks together and directs traffic between them, including to the internet. | 路由器 – 连接不同网络并在其间转发数据，包括连接到互联网。
- Wireless access point – Allows Wi-Fi devices to connect to a wired network. | 无线接入点 – 让 Wi-Fi 设备接入有线网络。
- Transmission media – Copper cable, fibre optic cable and wireless radio waves; fibre carries the most data over the longest distances. | 传输介质 – 铜缆、光纤和无线电波；光纤在最长距离上传输最多数据。
Every device on a network has a MAC address burned into its hardware, which never changes, and an IP address assigned by a network, which can change. A protocol is an agreed set of rules for communication: TCP/IP moves data across the internet, HTTP and HTTPS deliver web pages, FTP transfers files, and SMTP sends email.
网络上每个设备都有一个烧录在硬件中、永不改变的 MAC 地址，以及一个由网络分配、可以改变的 IP 地址。协议是通信的约定规则：TCP/IP 在互联网上传输数据，HTTP 和 HTTPS 传送网页，FTP 传输文件，SMTP 发送电子邮件。
Bandwidth is the amount of data a connection can carry per second, measured in megabits per second (Mbps). DNS (Domain Name System) translates a human-friendly address such as www.example.com into the numeric IP address that the network needs.
带宽是连接每秒能承载的数据量，单位为兆比特每秒（Mbps）。DNS（域名系统）把 www.example.com 这类便于人记忆的地址，转换成网络所需的数字 IP 地址。
8. Cyber Security | 网络安全
Cyber security means protecting data, software and systems from attack, damage or unauthorised access. It matters because a breach can cost money, break the law under data protection rules, and destroy trust.
网络安全是指保护数据、软件和系统免遭攻击、破坏或未经授权的访问。它之所以重要，是因为一次泄漏可能造成经济损失、违反数据保护法规，并摧毁信任。
- Virus – Malware that attaches to a file and spreads when the file is opened. | 病毒 – 依附在文件上、随文件被打开而传播的恶意软件。
- Worm – Malware that copies itself across networks without needing a host file. | 蠕虫 – 无需宿主文件即可自行在网络中复制传播的恶意软件。
- Trojan – Malware disguised as useful software, giving the attacker access. | 木马 – 伪装成有用软件的恶意程序，为攻击者提供访问权限。
- Ransomware – Encrypts the victim's files and demands payment to unlock them. | 勒索软件 – 加密受害者文件并索要赎金以解锁。
- Phishing – Fake emails or messages that trick users into revealing passwords or bank details. | 网络钓鱼 – 伪造邮件或消息，诱骗用户泄露密码或银行信息。
- Brute force attack – Programmatically trying huge numbers of password combinations. | 暴力破解 – 用程序尝试海量密码组合。
