📚 Quick Memory Guide to Key Computing Terms | 剑桥Year 9计算机术语速记指南
Building a strong vocabulary is like creating a mental toolkit for Year 9 Cambridge Computer Science. This guide pairs every term with a simple memory trick, helping you move from confusion to confidence. Work through each section to lock in the words that underpin algorithms, data, hardware, and networks.
对于剑桥 Year 9 计算机科学而言，建立扎实的术语库就像打造一套思维工具箱。本指南为每个术语都配上了简单的记忆窍门，帮助你从困惑走向自信。逐个章节认真学习，把支撑算法、数据、硬件和网络的词汇牢牢记在脑中。
1. Algorithms and Flowcharts | 算法与流程图
An algorithm is a precise, step-by-step set of instructions designed to solve a problem or complete a task. Think of it as a cooking recipe: each step must be followed in the correct order to get the right result.
算法是一组精确的、逐步的指令，用于解决问题或完成任务。可以把它想象成一份烹饪食谱：必须按正确顺序执行每一步，才能得到正确的结果。
Flowcharts use standard symbols to visualise an algorithm. The oval is the start/stop terminal, the rectangle represents a process, the diamond shows a decision, and arrows indicate the flow of control.
流程图使用标准符号将算法可视化。椭圆是开始/结束端子，矩形代表处理步骤，菱形表示判断，箭头则指示控制流向。
Quick memory trick: 'Al-Go-Rhythm' sounds like a dance with a fixed beat—an algorithm has a fixed sequence. For flowcharts, diamond decisions look like a crossroads where you pick a path.
速记窍门：'Al-Go-Rhythm' 听起来像有固定节拍的舞蹈——算法正有固定的顺序。对于流程图，菱形的判断框就像一个交叉路口，你在那里选择一条路径。
2. Variables and Data Types | 变量与数据类型
A variable is a named container in memory that stores a value which can change while the program runs. Imagine a labelled locker: you put something in, but you can swap the contents later.
变量是内存中有名字的容器，存储着在程序运行期间可以改变的值。想象一个贴着标签的储物柜：你把东西放进去，但之后可以更换里面的内容。
Common data types define what kind of data a variable can hold. An integer is a whole number (e.g., 7, -2), a float/real holds decimals (e.g., 3.14), a string stores text in quotes (e.g., 'Hello'), and a Boolean is either TRUE or FALSE.
常见的数据类型定义了变量能保存什么类型的数据。整数(integer)是整数（如7, -2），浮点数(float/real)存放小数（如3.14），字符串(string)存储引号中的文本（如'Hello'），而布尔值(Boolean)只能是 TRUE 或 FALSE。
Memory hack: think of a variable as a named box, and its data type as the shape of items that can fit inside. A box labelled 'age' only takes whole numbers (integer), while 'username' takes a string of letters.
记忆技巧：把变量看作一个带名字的盒子，数据类型就是盒子能容纳的物品形状。标着'age'的盒子只接受整数，而'username'接受一串字母组成的字符串。
3. Operators and Expressions | 运算符与表达式
Operators are symbols that tell the computer to perform specific mathematical or logical manipulations. Arithmetic operators include + (addition), - (subtraction), * (multiplication), / (division), and MOD (remainder after division).
运算符是告诉计算机执行特定数学或逻辑操作的符号。算术运算符包括 +（加）、-（减）、*（乘）、/（除）和 MOD（除法取余数）。
son operators return a Boolean result (TRUE/FALSE) by comparing two values: == (equal to), ! eater than), < (less than), >= (greater than or equal to), and <= (less than or equal to).
比较运算符通过比较两个值返回布尔结果（TRUE/FALSE）：==（等于）、!=（不等于）、>（大于）、<（小于）、>=（大于等于）和 <=（小于等于）。
perators that the computer evaluates to produce a result, such as score + 10 or age >= 13.
表达式是值、变量和运算符的组合，计算机会对其求值并得出结果，例如 score + 10 或 age >= 13。
Memory aid: the single equals sign '=' means assignment (put a value in the box), while double equals '==' asks 'are these equal?'. MOD reminds you to think of leftover slices after sharing a pizza—7 MOD 3 gives 1 slice left.
记忆窍门：单等号 '=' 意为赋值（把值放入盒子），双等号 '==' 则是提问'这两个相等吗？'。MOD 则让你联想分完披萨后剩下的那一块——7 MOD 3 结果就是剩1块。
4. Selection: IF-ELSE Statements | 选择结构：IF-ELSE 语句
Selection allows a program to make decisions and choose different paths based on conditions. An IF statement runs a block of code only when a condition is TRUE. An ELSE block runs when the condition is FALSE. You can extend this with ELSE IF to test multiple conditions.
选择结构让程序能够根据条件做出判断，选择不同的执行路径。IF 语句仅在条件为 TRUE 时运行一段代码。ELSE 块则在条件为 FALSE 时运行。还可以用 ELSE IF 扩展，来测试多个条件。
Structure example:
IF temperature > 30 THEN
PRINT 'Stay cool'
ELSE
PRINT 'Wear a jacket'
END IF
结构示例：
IF temperature > 30 THEN
PRINT 'Stay cool'
ELSE
PRINT 'Wear a jacket'
END IF
trick: imagine a fork in a road. You look at the signpost (the condition), and if it says 'Beach Open = TRUE' you go straight. In code, the program looks at the condition to decide which block to run.
视觉记忆法：想象一条分岔路。你看着路牌（条件），如果写着'海滩开放 = TRUE'，就向左转；否则直行。在代码中，程序查看条件来决定执行哪一个代码块。
5. Iteration: Count-Controlled and Condition-Controlled Loops | 循环结构：计数控制与条件控制循环
Iteration means repeating a set of instructions. A count-controlled loop (FOR loop) repeats a block a specific number of times. For example, FOR i ← 1 TO 5 will run five times.
循环的意思就是重复执行一组指令。计数控制循环（FOR 循环）将一段代码重复执行指定的次数。例如，FOR i ← 1 TO 5 将运行五次。
A condition-controlled loop (WHILE or REPEAT...UNTIL) keeps looping as long as a condition is TRUE. A WHILE loop checks the condition at the start; a REPEAT loop checks at the end, guaranteeing at least one execution.
条件控制循环（WHILE 或 REPEAT...UNTIL）只要条件为 TRUE 就持续循环。WHILE 循环在开头检查条件；REPEAT 循环在结尾检查，确保至少执行一次。
Key terminology: a counter is a variable that tracks how many times a loop has run; an increment is the step value added to the counter each time.
关键术语：计数器(counter)是一个跟踪循环已运行次数的变量；增量(increment)是每次循环中计数器增加的值。
Memory hook: think of a FOR loop like a countdown timer for an egg—you know exactly how many minutes to wait. A WHILE loop is like waiting for a bus—you keep waiting until the bus arrives (condition becomes FALSE).
记忆挂钩：把 FOR 循环想象成一个煮蛋计时器——你确切知道要等待多少分钟。WHILE 循环则像等公交车——你一直等到公交车到达（条件变为 FALSE）为止。
6. Binary and Data Representation | 二进制与数据表示
Computers use binary, a base‑2 number system with only two digits: 0 and 1. Each binary digit is called a bit. A group of 8 bits is a byte, often used to represent a character using codes like ASCII.
计算机使用二进制，一种只有两个数字 0 和 1 的基数为 2 的数字系统。每个二进制数位称为一个比特(bit)。8个比特组成一个字节(byte)，常用 ASCII 等编码表示一个字符。
=128. To convert from binary to denary (base 10), add the place values where there is a 1.
二进制位值是 2 的幂，从右往左：2°=1, 2¹=2, 2²=4, 2³=8, 2⁴=16, 2⁵=32, 2⁶=64, 2⁷=128。将二进制转换为十进制时，把出现 1 的位值相加即可。
binary number. For example, 13 in denary: 13÷2=6 R1, 6÷2=3 R0, 3÷2=1 R1, 1÷2=0 R1 → 1101.
十进制转二进制使用重复除以2的方法。余数从下往上读取就是二进制数。例如十进制 13：13÷2=6 余1, 6÷2=3 余0, 3÷2=1 余1, 1÷2=0 余1 → 1101。
Quick recall: 'binary is on–off switches'. A light switch has two states, just like a bit. For place values, remember the little rhyme: '1, 2, 4, 8, binary makes computers great!'
快速回想：'二进制就是开关状态'。一个电灯开关有两种状态，就像比特一样。对于位值，记住小韵文：'1, 2, 4, 8, 二进制让计算机真棒！'
7. Logic Gates and Truth Tables | 逻辑门与真值表
Logic gates are tiny electronic circuits that perform Boolean operations on one or more inputs to produce a single output. The three core gates are NOT, AND, and OR.
逻辑门是微小的电子电路，对一路或多路输入执行布尔运算，产生单路输出。三个核心门是 NOT门、AND门 和 OR门。
A NOT gate takes one input and flips it: input 0 gives output 1; input 1 gives output 0. An AND gate gives output 1 only when both inputs are 1. An OR gate gives output 1 when at least one input is 1.
非门(NOT) 接受一路输入并将其翻转：输入 0 输出 1；输入 1 则输出 0。与门(AND) 仅当两路输入都为 1 时才输出 1。或门(OR) 当至少一路输入为 1 时就输出 1。
A truth table lists every possible combination of inputs and the corresponding output for a logic gate or circuit. It helps verify the logical behaviour before building the circuit.
真值表列出了逻辑门或电路所有可能的输入组合及其对应的输出。它有助于在构建电路前验证逻辑行为。
Memory aid: NOT is like a rebellious teenager who always does the opposite. AND is strict—only says YES when everyone agrees. OR is easy-going—says YES if anyone wants to. Truth tables are like a complete menu of possibilities.
记忆窍门：NOT 门像一个叛逆的青少年，总是反着来。AND 门很严格——只有所有人都同意时才说 YES。OR 门比较随和——只要有人想去就说 YES。真值表就像一张完整的可能性菜单。
8. Networks and the Internet | 网络与互联网
A computer network is two or more devices connected together to share resources and data. Key hardware includes switches, routers, and network interface cards (NICs).
计算机网络是两个或以上的设备连接在一起，以共享资源和数据。关键硬件包括交换机(switch)、路由器(router)和网络接口卡(NIC)。
The internet is a global network of networks. The World Wide Web (WWW) is a collection of web pages accessed via the internet using the HTTP/HTTPS protocol. A URL (Uniform Resource Locator) is the address of a specific web page.
互联网是全球性的网络之网。万维网(WWW)是通过互联网使用 HTTP/HTTPS 协议访问的网页集合。URL（统一资源定位符）是特定网页的地址。
An IP address uniquely identifies a device on a network, like a postal address. A MAC address is a permanent hardware identifier burned into the NIC.
IP 地址在网络上唯一标识一台设备，就像邮政地址。MAC 地址是写入网卡的永久硬件标识符。
Key protocols: TCP/IP breaks data into packets and reassembles them, ensuring reliable delivery. DNS translates domain names (like aleveler.com) into IP addresses.
关键协议：TCP/IP 将数据分成数据包并重新组装，确保可靠交付。DNS 将域名（如 aleveler.com）转换为 IP 地址。
Memory trick: imagine sending a letter. IP address is the house address, MAC address is the house itself (never changes), DNS is a phonebook turning names into numbers, and TCP/IP is the postal service that guarantees delivery.
记忆技巧：想象寄信。IP 地址是房屋地址，MAC 地址是房屋本身（永不变），DNS 是将名字转为号码的电话簿，而 TCP/IP 是保证送达的邮政服务。
9. Hardware and Software | 硬件与软件
Hardware refers to the physical components of a computer system. The CPU (Central Processing Unit) is the 'brain' that executes instructions. It fetches, decodes, and executes using the fetch–decode–execute cycle.
硬件指计算机系统的物理组件。CPU（中央处理器）是执行指令的'大脑'，利用取指–解码–执行周期来工作。
Memory hierarchy: RAM (Random Access Memory) is volatile, fast memory that holds data and programs currently in use. ROM (Read Only Memory) is non‑volatile, holding boot‑up instructions. Secondary storage (HDD, SSD) provides long‑term storage.
内存层次：RAM（随机存取存储器）是易失性快速存储器，保存当前正在使用的数据和程序。ROM（只读存储器）是非易失性的，保存启动指令。辅助存储器（HDD, SSD）提供长期存储。
Software is the set of programs that run on hardware. System software includes the operating system (OS), which manages hardware and provides a user interface. Application software lets users perform specific tasks, like word processing or web browsing.
软件是在硬件上运行的程序集合。系统软件包括操作系统(OS)，它管理硬件并提供用户界面。应用软件让用户执行特定任务，如文字处理或浏览网页。
Quick recall: 'Hardware is what you can kick, software is what you can swear at.' RAM is your short‑term memory that vanishes when you sleep (turn off); ROM is the ingrained habit that stays. The fetch–decode–execute cycle is like a robot: get instruction, understand it, do it.
快速回想：'硬件是你能踢到的东西，软件是你能骂的东西。' RAM 像短期记忆，一睡觉（关机）就消失；ROM 是根深蒂固的习惯，不会消失。取指–解码–执行周期好比机器人：取指令、理解、执行。
10. Cybersecurity and Data Safety | 网络安全与数据安全
Cybersecurity protects systems, networks, and data from digital attacks. Malware is malicious software, including viruses (self‑replicating, damaging), worms (spread without user action), and trojans (disguised as legitimate software).
网络安全保护系统、网络和数据免受数字攻击。恶意软件是恶意程序，包括病毒（自我复制、破坏性）、蠕虫（无需用户操作即可传播）和特洛伊木马（伪装成合法软件）。
Phishing uses deceptive emails or messages to trick users into revealing personal information. A brute‑force attack tries every possible password. A firewall monitors and controls incoming and outgoing network traffic based on security rules.
网络钓鱼使用欺诈性电子邮件或消息诱骗用户泄露个人信息。暴力攻击尝试每个可能的密码。防火墙根据安全规则监控和控制进出网络流量。
Encryption scrambles data into ciphertext using a key, so only authorised parties with the decryption key can read it. Authentication verifies identity, often through passwords or biometrics.
加密使用密钥将数据打乱成密文，只有拥有解密密钥的授权方才能读取。认证验证身份，通常通过密码或生物识别。
Key protective measures: strong passwords (mix of characters), regular updates, two‑factor authentication (2FA), and not sharing sensitive data openly.
关键防护措施：强密码（字符混合）、定期更新、双因素身份验证(2FA)，以及不公开共享敏感数据。
Memory hook: imagine your data as a treasure chest. Encryption puts a padlock on it, a firewall is a guarded gate, phishing is a fake treasure map, and 2FA is a secret handshake in addition to the key. 'If it sounds too good, it's probably a scam' helps spot phishing.
记忆挂钩：把你的数据想象成一个宝箱。加密给它加上挂锁，防火墙是带守卫的大门，网络钓鱼是假的藏宝图，而双因素身份验证是在钥匙之外再握个秘密手。'如果听起来好得不像是真的，那可能就是骗局'——这能帮你识破网络钓鱼。
11. Computational Thinking Terms | 计算思维术语
Computational thinking is the thought process involved in formulating problems so they can be solved by computers. Decomposition breaks a complex problem into smaller, manageable parts. Pattern recognition spots similarities among problems.
计算思维是将问题表述成可由计算机解决的形式的思维过程。分解(decomposition)将一个复杂问题拆分成更小、更易处理的部分。模式识别(pattern recognition)发现不同问题间的相似之处。
Abstraction focuses on the important information only, ignoring irrelevant details. Algorithm design finally creates the step‑by‑step solution. Together, these form the four cornerstones of computational thinking.
抽象(abstraction)只关注重要信息，忽略无关细节。算法设计最终创建逐步解决方案。这四者构成了计算思维的四大基石。
Think of decomposition as eating an elephant one bite at a time; abstraction as drawing a stick figure instead of a photorealistic portrait; and pattern recognition as realising the same ingredients appear in both cakes and pancakes.
想象分解是'一口一口地吃掉大象'；抽象是画火柴人而非照片级肖像；模式识别则是发现同样的原料既出现在蛋糕里也出现在煎饼里。
12. Common File Formats and Extensions | 常见文件格式与扩展名
Files use extensions to indicate their format. .docx is a Microsoft Word document, .pdf is a Portable Document Format that preserves layout, .jpg or .jpeg is a compressed image, .png supports transparent backgrounds, .mp3 is an audio file, and .mp4 is a video container.
文件使用扩展名来表示其格式。.docx 是微软 Word 文档，.pdf 是可移植文档格式能保留排版，.jpg 或 .jpeg 是压缩图像，.png 支持透明背景，.mp3 是音频文件，而 .mp4 是视频容器。
Executable files like .exe (Windows) run programs. .zip compresses multiple files into one archive. Knowing extensions helps users choose the right software to open a file.
可执行文件如 .exe（Windows）能运行程序。.zip 将多个文件压缩成一个存档。了解扩展名有助于用户选择合适的软件打开文件。
Memory trick: think of extensions as a label on a food can telling you if it's soup, beans, or fruit—you'd use a different opener for each. .pdf is like a sealed document that looks the same everywhere. .png carries a 'transparent cloak' for images.
记忆技巧：把扩展名想象成食品罐头的标签，告诉你里面是汤、豆子还是水果——开不同的罐头要用不同的开罐器。.pdf 像一份密封文档，在任何地方看起来都一样。.png 为图像披上了一件'透明斗篷'。
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