📚 Year 11 CAIE Computer Science: Vocabulary & Terminology Quick-Memorisation Guide | 剑桥CAIE计算机科学词汇术语速记指南
Mastering the theoretical paper in CAIE IGCSE Computer Science often comes down to precise use of terminology. A clear definition can earn you the mark, while a vague description loses it. This guide presents high-frequency terms paired with mnemonic tricks, word-root analysis, and comparative tables, helping you move from passive recognition to active recall under exam pressure.
在CAIE IGCSE计算机科学的理论考试中，精准的术语使用往往决定得分与否。清晰的定义能帮你稳拿分数，而模糊的描述则会导致失分。这份指南将高频术语与速记窍门、词根分析和对比表格相结合，帮助你在考试压力下从被动识别转向主动回忆。
1. Algorithm & Pseudocode | 算法与伪代码
An algorithm is a step-by-step, finite sequence of instructions to solve a problem. Pseudocode is a structured, readable notation that describes an algorithm without strict programming language syntax. The key exam phrase is 'unambiguous' — algorithms must leave no room for interpretation.
算法是解决某个问题的逐步的、有限步骤序列。伪代码是一种结构化、可读的记法，用于描述算法而无需严格遵循编程语言语法。考试中的关键词是“无歧义”——算法不能留有任何解读空间。
To memorise 'pseudo', think of 'fake code' s like code but computers cannot execute it directly. Always remember the three algorithmic building blocks demanded by CAIE: sequence, selection, iteration.
记忆“伪”这个词，可联想“假装代码”。Pseudo = 假（希腊词根）。它看上去像代码，但计算机不能直接执行。要记住CAIE要求的三个算法构造块：顺序、选择和迭代。
Typical pseudocode keywords: INPUT, OUTPUT, IF...THEN...ELSE...ENDIF, WHILE...DO...ENDWHILE, FOR...TO...NEXT. Use capital letters as required in the syllabus. This consistency signals you know the standard.
典型的伪代码关键词：INPUT, OUTPUT, IF...THEN...ELSE...ENDIF, WHILE...DO...ENDWHILE, FOR...TO...NEXT。按大纲要求使用大写字母。这种一致性表明你了解标准。
2. Data Types & Variable Declarations | 数据类型与变量声明
A variable is a named storage location that holds a value which can change during execution. A constant holds a value that cannot be changed. The five fundamental data types in CAIE pseudocode are: INTEGER, REAL, CHAR, STRING, BOOLEAN.
变量是一个命名的存储位置，其保存的值在执行过程中可以改变。常量保存不可变的值。CAIE伪代码中的五种基本数据类型是：INTEGER、REAL、CHAR、STRING、BOOLEAN。
Mnemonic for data types: I R C S B — 'I Really Can Sing Ballads' ly . Associate BOOLEAN with only two values: TRUE and FALSE. Real numbers include decimals; integers do not. A string is 'a chain of characters' — string = chain.
数据类型速记：I R C S B——“我真的会唱歌谣”。将BOOLEAN与仅两个值关联：TRUE和FALSE。实数包含小数；整数不包含。字符串是“字符串”——string = 链。
CAIE declarations: DECLARE name : STRING or CONSTANT Pi = 3.14. Note the use of a colon and the specific spelling. Remember 'DECLARE' not 'DIM' like in some older texts.
CAIE声明形式：DECLARE name : STRING 或 CONSTANT Pi = 3.14。注意冒号的使用和特定的拼写。记住是'DECLARE'，而非某些旧教材中的'DIM'。
3. Sequence, Selection & Iteration | 顺序、选择与迭代
Sequence means instructions are executed line-by-line in order. Selection allows decision-making using conditions — IF, CASE/OTHERWISE. Iteration allows repetition — count-controlled (FOR loop), condition-controlled (WHILE, REPEAT/UNTIL).
顺序意味着指令逐行按次序执行。选择允许使用条件进行决策——IF、CASE/OTHERWISE。迭代允许重复——计数控制循环（FOR循环），条件控制循环（WHILE、REPEAT/UNTIL）。
n = stir until dissolved. Relating these abstract concepts to daily routines cements them.
想象泡茶：顺序 = 烧水 -> 加茶叶 -> 倒水（固定次序）。选择 = 如果不加糖，就免去甜味剂。迭代 = 搅拌直至溶解。把这些抽象概念与日常惯例关联起来能巩固记忆。
In exams, never confuse WHILE with REPEAT. A WHILE loop tests the condition at the beginning; the loop may execute zero times. A REPEAT/UNTIL loop tests at the end and executes at least once.
考试时，绝不要混淆WHILE和REPEAT。WHILE循环在开头测试条件，可能一次也不执行。REPEAT/UNTIL循环在结尾测试，至少执行一次。
- WHILE condition DO ... ENDWHILE — pre-condition loop.
- WHILE 条件 DO ... ENDWHILE — 前置条件循环。
- REPEAT ... UNTIL condition — post-condition loop.
- REPEAT ... UNTIL 条件 — 后置条件循环。
4. Arrays, Indices & 2D Structures | 数组、索引与二维结构
An array is a finite, indexed collection of elements of the same data type. The index is an ordinal number (usually integer) that identifies an element’s position. CAIE uses 1-based indexing by default in pseudocode unless stated otherwise.
数组是一个有限的、带索引的、由相同数据类型的元素构成的集合。索引是用来标识元素位置的序数（通常为整数）。CAIE伪代码默认使用从1开始的索引，除非另有说明。
To memorise the difference between 1D and 2D arrays: 1D array is a row of lockers. 2D array is a grid with rows and columns — like a cinema seat plan with a row number and a seat number.
记忆一维和二维数组的区别：一维数组是一排储物柜。二维数组是有行和列的网格——就像电影院的座位图，有排号和座号。
Declaration: DECLARE StudentMarks : ARRAY[1:30] OF INTEGER. The range notation [lower:upper] is vital. For a 2D array: ARRAY[1:6, 1:5] OF REAL. Write carefully: comma separates dimensions.
声明形式：DECLARE StudentMarks : ARRAY[1:30] OF INTEGER。范围记号[lower:upper]至关重要。二维数组：ARRAY[1:6, 1:5] OF REAL。书写要仔细：逗号分隔维度。
5. Number Bases: Binary, Denary & Hexadecimal | 数制：二进制、十进制与十六进制
Binary is base-2 (digits 0, 1). Denary/decimal is base-10 (0–9). Hexadecimal is base-16 (0–9, A–F). These number systems are the backbone of data representation. The syllabus requires conversion between them and understanding why hex is used (shorter, less error-prone than long binary strings).
二进制是基数为2（数字0、1）。十进制是基数为10（0–9）。十六进制是基数为16（0–9、A–F）。这些数制是数据表示的基石。大纲要求能在它们之间进行转换，并理解使用十六进制的原因（比长长的二进制串更短、更不易出错）。
ectly to one hex digit. Memorise hex letters A=10, B=11, C=12, D=13, E=14, F=15. The rhyme 'A ten, B eleven, C twelve, D thirteen, E fourteen, F fifteen' is simple and effective.
转换诀窍：二进制转十六进制，从右向左每四位一组。一个半字节（4位）直接对应一位十六进制数字。记住十六进制字母：A=10, B=11, C=12, D=13, E=14, F=15。顺口溜“A十，B十一，C十二，D十三，E十四，F十五”简单有效。
For binary to denary, use the place-value table with powers of 2: ...128, 64, 32, 16, 8, 4, 2, 1. Underline the positions with 1s and add the corresponding values. Reverse the process for denary to binary by successive division by 2.
二进制转十进制，使用权重为2的幂的位值表：...128、64、32、16、8、4、2、1。在1对应的位下方划线，然后加总对应值。十进制转二进制则通过连续除以2取余数来逆向操作。
6. Data Storage Units & File Sizes | 数据存储单位与文件大小
Bit (b) is a single binary digit. Nibble is 4 bits. Byte (B) is 8 bits. Kilobyte (kB), Megabyte (MB), Gigabyte (GB), Terabyte (TB) follow. CAIE expects you to know that file size is measured in bytes, and memory addresses are measured in bits or bytes.
比特(b)是一个二进制位。半字节是4位。字节(B)是8位。之后是千字节(kB)、兆字节(MB)、吉字节(GB)、太字节(TB)。CAIE要求知道文件大小以字节度量，内存地址以比特或字节度量。
A classic comparison: a nibble is 'half a bite' — , so nibble is a small bite. 8 bits = 1 byte. Then 1024 bytes = 1 kB (not 1000; remember 210). Use the phrase '1024 bytes in a kilo' as your chant.
经典类比：半字节是“一小口”——byte发音像bite，nibble就是一小口。8位 = 1字节。然后1024字节 = 1 kB（不是1000；记住是2¹⁰）。用这句话作为口号：“千字节里1024个字节”。
Exam pitfall: Differences between kB and KiB are not in IGCSE; stick to 1024. Also distinguish between a bit and a byte when referring to data transfer speeds — network speeds are often in bits per second (bps), while file storage uses bytes.
考试陷阱：IGCSE不涉及kB与KiB的区别；统一使用1024。还要区分比特和字节在提及数据传输速度时的不同——网络速度通常为每秒比特数(bps)，而文件存储则用字节。
7. Logic Gates & Truth Tables | 逻辑门与真值表
The six elementary logic gates in CAIE are: NOT, AND, OR, NAND, NOR, XOR. Each has a distinct symbol and truth table. You must be able to draw them and complete a truth table for a given combination of gates.
CAIE涉及的六个基本逻辑门是：NOT、AND、OR、NAND、NOR、XOR。每个都有独特的符号和真值表。你必须能画出它们，并为给定的门组合完成真值表。
| Gate | 门 | Quick Memory Aid | 快速记忆法 | Output 1 When | 输出1的条件 |
|---|---|---|
| AND | Both inputs must be 1 (like a double lock) | A=1 AND B=1 |
| OR | At least one input 1 (any 1 gives 1) | A=1 OR B=1 |
| NOT | Flips the input (inverter) | Input is 0 |
| NAND | NOT AND — output opposite of AND | Any input is 0 |
| NOR | NOT OR — output 1 only when both inputs 0 | A=0 and B=0 |
| XOR | Exclusive OR — one and only one input 1 | Inputs are different |
Truth table headings must be labelled clearly, e.g., A, B, C, Output. The number of rows is 2n where n is the number of inputs. For two inputs, 4 rows; for three inputs, 8 rows. Use binary counting pattern (000,001,010...) to populate rows without missing any.
真值表的表头必须清楚标记，如A、B、C、输出。行数为2ⁿ，其中n是输入个数。两个输入则4行；三个输入则8行。使用二进制计数模式（000、001、010...）来填充各行，避免遗漏。
8. Network Hardware & Protocols | 网络硬件与协议
A router forwards data packets between networks using IP addresses. A switch connects devices within a LAN and uses MAC addresses to send frames only to the intended recipient. A hub (outdated) broadcasts to all ports. Know the difference: switch is intelligent, hub is not.
路由器使用IP地址在网络之间转发数据包。交换机在局域网内部连接设备，并使用MAC地址仅将帧发送给目标接收者。集线器（已过时）向所有端口广播。要清楚区别：交换机是智能的，集线器不是。
(secure version with encryption), FTP (File Transfer Protocol), SMTP (Simple Mail Transfer — sends emails), POP3/IMAP (retrieve emails). The clever trick: 'HTTP = HyperText, FTP = File Transfer, SMTP = Send Mail To People'.
协议是一组规则。将它们与缩写关联：HTTP用于网页，HTTPS（加密的安全版本），FTP（文件传输协议），SMTP（简单邮件传输——发送邮件），POP3/IMAP（接收邮件）。巧记法：“HTTP=超文本，FTP=传文件，SMTP=送邮件给人”。
IP addresses (IPv4) consist of four denary numbers separated by dots, each 0– C. IP address = where you are; MAC address = who you are. This analogy prevents confusion.
IP地址(IPv4)由四个用点分隔的十进制数组成，每个数范围0–255。MAC地址是烧录在网卡中的48位十六进制标识符。IP地址=你在哪里；MAC地址=你是谁。这个类比预防混淆。
9. Database Terminology | 数据库术语
A database is a structured collection of related data. A table is a set of records (rows). A record is a set of fields (columns) about one entity. A field contains a single data item. A primary key uniquely identifies each record. A foreign key creates a relationship by referencing a primary key in another table.
数据库是有组织的相关数据集合。表是一系列记录（行）。记录是关于某个实体的一组字段（列）。字段包含单个数据项。主键唯一标识每条记录。外键通过引用另一表的主键来创建关系。
Mnemonic: 'P-Key is President (one and only one), F-Key is Foreign Ambassador'. A primary key must be unique and not null. Foreign keys can be repeated. For queries, QBE (query by example) uses grid forms, while SQL uses text commands like SELECT * FROM Students WHERE Grade > 80.
记忆法：“主键是总统（独一无二），外键是外国大使”。主键必须唯一且非空。外键可重复。对于查询，QBE（按例查询）使用网格表单，而SQL使用文本命令，如SELECT * FROM Students WHERE Grade > 80。
Data types in databases broadly map to those in programming: text (STRING), number (INTEGER/REAL), date/time, Boolean. For design, remember redundancy is evil — normalisation reduces duplication.
数据库中的数据类型与编程中的大致对应：文本(STRING)、数字(INTEGER/REAL)、日期/时间、布尔型。设计时，记住冗余是大忌——规范化能减少重复。
10. Cybersecurity Threats & Safeguards | 网络安全威胁与防范
Malware is malicious software: virus (attaches to files, spreads when executed), worm (self-replicates without host), Trojan horse (disguised as legitimate software). Phishing is a social engineering attack using fake emails/websites to steal credentials. A brute-force attack tries all possible passwords.
恶意软件是恶意软件：病毒（附着于文件，执行时传播），蠕虫（无需宿主自复制），特洛伊木马（伪装成合法软件）。网络钓鱼是一种社会工程攻击，使用伪造的电子邮件/网站窃取凭证。暴力破解攻击尝试所有可能的密码。
cryption scrambles data using an algorithm and a key; plaintext becomes ciphertext. SSL/TLS provides secure communication. 'Firewall = wall of fire; Proxy = substitute; Encryption = secret code'.
防御术语：防火墙根据规则监控和过滤网络流量。代理服务器充当中介，隐藏内部IP。加密使用算法和密钥打乱数据；明文变成密文。SSL/TLS提供安全通信。'Firewall = 火墙；Proxy = 代理；Encryption = 秘密代码'。
Anti-malware and anti-virus software detect and remove threats using signature databases and heuristic analysis. Regular updates, strong passwords, and two-factor authentication are essential user safeguards.
反恶意软件和防病毒软件利用特征数据库和启发式分析来检测并清除威胁。定期更新、强密码和双因素认证是必要的用户防护措施。
11. Assembly & Machine Code Concepts | 汇编与机器码概念
Machine code is the binary instruction that a CPU directly executes. Assembly language uses mnemonic codes (like LDA, STA, ADD) that map one-to-one to machine code instructions. An assembler translates assembly to machine code. High-level languages (Python, Java) are translated by compilers or interpreters.
机器码是CPU直接执行的二进制指令。汇编语言使用助记符（如LDA、STA、ADD），与机器码指令一一对应。汇编器将汇编语言翻译成机器码。高级语言（Python、Java）由编译器或解释器翻译。
For the Little Man Computer (LMC) or similar model, memorise mnemonics: LDA (load), STA (store), ADD, SUB, INP (input), OUT (output), BRP (branch if positive), BRZ (branch if zero), BRA (branch always), HLT (halt). Create a story: 'Little Man Always Does Stuff, BRinging Always Halts'. Silly, but memorable.
对于小人计算机(LMC)或类似模型，记忆助记符：LDA（加载）、STA（存储）、ADD、SUB、INP（输入）、OUT（输出）、BRP（正则跳转）、BRZ（零则跳转）、BRA（无条件跳转）、HLT（停机）。编个故事：“小人总是做事情，带东西一直停”。有点傻，但好记。
Understand the registers within the CPU: PC (Program Counter, holds address of next instruction), MAR (Memory Address Register), MDR (Memory Data Register), CIR (Current Instruction Register), ACC (Accumulator). 'PC points to next, MAR holds the address, MDR fetches the data, CIR decodes, ACC calculates.'
理解CPU内部的寄存器：PC（程序计数器，存放下一条指令地址），MAR（内存地址寄存器），MDR（内存数据寄存器），CIR（当前指令寄存器），ACC（累加器）。'PC指向下一个，MAR保存地址，MDR取数据，CIR译码，ACC计算。'
12. Revision Shortcuts & Exam Command Words | 复习捷径与考试指令词
CAIE uses specific command words: State (give a concise answer, no explanation), Describe (say what happens, possibly with steps), Explain (give reasons, cause and effect), Identify (name or list). Always match your answer length to the mark allocation and command word.
CAIE使用特定的指令词：State（给出简洁答案，无需解释），Describe（说明发生什么，可含步骤），Explain（给出理由、因果关系），Identify（指出或列出）。始终使答案长度与分值和指令词相匹配。
Build a terminology journal: one column for the term, one for the definition, one for a mnemonic or diagram. Review actively by covering the definition and trying to recall. For pairs like 'Lossy vs Lossless compression', use a Venn diagram or a two-column table to contrast.
建立一个术语日志：一列写术语，一列写定义，一列写记忆术或图表。主动复习时遮住定义，尝试回忆。对于像“有损压缩与无损压缩”这样的对比术语，使用维恩图或两列表格进行对照。
Finally, when stuck on a term like 'checksum' or 'parity bit', break it down: check-sum is a sum used to check; parity bit is a bit that makes the number of 1s even (even parity) or odd (odd parity). Focus on the purpose: error detection, not correction (in most IGCSE contexts).
最后，当遇到像“校验和”或“奇偶校验位”这样的术语时，将其拆解：check-sum是用于检查的总和；parity bit是使1的个数为偶数（偶校验）或奇数（奇校验）的位。关注其目的：错误检测，而非纠正（在多数IGCSE语境中）。
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