IB & WJEC Computer Science: Mind Map Quick Revision | IB与WJEC计算机科学：思维导图速记

📚 IB & WJEC Computer Science: Mind Map Quick Revision | IB与WJEC计算机科学：思维导图速记

Struggling to keep all the computer science topics in your head for IB or WJEC exams? A mind map revision technique helps you visualise connections between system architecture, data representation, networking, algorithms, and ethical considerations. This article organises core concepts into a structured mind map, with bilingual explanations for quick memorisation. Treat each section as a branch off the central theme: Computer Science Fundamentals.

正在为IB或WJEC计算机科学考试的知识点记忆发愁吗？思维导图速记法能帮你直观地看出系统架构、数据表示、网络、算法和伦理考量之间的联系。本文将核心概念组织成结构化的思维导图，配以中英双语解释，便于快速记忆。请把每一节都看作从中心主题“计算机科学基础”延伸出去的分支。

1. System Architecture | 系统架构

The central processing unit (CPU) is the brain of a computer, executing instructions via the fetch-decode-execute cycle. Key components include the Control Unit (CU), Arithmetic Logic Unit (ALU), and registers such as the Program Counter (PC), Memory Address Register (MAR), and Memory Data Register (MDR). The von Neumann architecture stores both data and instructions in the same memory.

中央处理器（CPU）是计算机的大脑，通过取指-解码-执行周期运行指令。核心部件包括控制单元（CU）、算术逻辑单元（ALU）以及程序计数器（PC）、内存地址寄存器（MAR）和内存数据寄存器（MDR）等寄存器。冯·诺依曼架构将数据和指令存放在同一个内存中。

Clock speed, measured in hertz, determines how many cycles per second the CPU can perform. Cores allow parallel processing, and cache memory (L1, L2, L3) provides high-speed data access to reduce the von Neumann bottleneck. Embedded systems are specialised computers within larger devices, often with real-time constraints.

时钟速度以赫兹为单位，决定了CPU每秒可执行多少个周期。多核支持并行处理，而缓存内存（L1、L2、L3）提供高速数据访问以减少冯·诺依曼瓶颈。嵌入式系统是嵌入在大型设备中的专用计算机，通常具有实时性约束。

2. Data Representation | 数据表示

Computers store all data as binary (0s and 1s). A bit is the smallest unit; a nibble is 4 bits; a byte is 8 bits. Denary (base‑10) numbers convert to binary, hexadecimal (base‑16: 0‑9, A‑F), and vice versa. Binary addition follows rules like 1+1 = 0 carry 1. Negative numbers can be represented using sign-and-magnitude or two’s complement, where the most significant bit (MSB) indicates sign.

计算机将所有数据存储为二进制（0和1）。位是最小单位；半字节是4位；一个字节是8位。十进制（基数为10）数字可以转换为二进制、十六进制（基数为16：0‑9, A‑F），反之亦然。二进制加法遵循如1+1=0进1等规则。负数可用原码或补码表示，其中最高有效位（MSB）指示符号。

Characters are encoded using ASCII (7‑bit, extended 8‑bit) or Unicode. Images consist of pixels; resolution and colour depth (bits per pixel) affect file size. Sound is sampled at a frequency and bit depth to convert analogue waves to digital. Compression can be lossy (e.g., JPEG, MP3) or lossless (e.g., PNG, ZIP).

字符通过ASCII（7位，扩展8位）或Unicode编码。图像由像素组成；分辨率和颜色深度（每像素位数）影响文件大小。声音以采样频率和位深度将模拟波转换为数字。压缩可以是有损（如JPEG、MP3）或无损（如PNG、ZIP）。

Denary	Binary (8‑bit)	Hexadecimal
10	00001010	0A
255	11111111	FF

3. Computer Networks | 计算机网络

A network connects devices to share resources. LANs cover small areas; WANs span large geographical distances. Topologies include star, bus, ring, and mesh. The Internet is a global WAN using TCP/IP protocols. IP addresses (IPv4: 32‑bit, IPv6: 128‑bit) identify devices, while MAC addresses are hardware‑based identifiers.

网络连接设备以共享资源。局域网覆盖小范围；广域网跨越长地理距离。拓扑结构包括星型、总线、环型和网状。互联网是一个使用TCP/IP协议的全球广域网。IP地址（IPv4：32位，IPv6：128位）识别设备，而MAC地址是基于硬件的标识符。

The TCP/IP model has four layers: Application (HTTP, FTP, SMTP), Transport (TCP, UDP), Internet (IP), and Link (Ethernet). DNS converts domain names to IP addresses. Packet switching breaks data into packets that travel independently. Client‑server and peer‑to‑peer are common network models.

TCP/IP模型有四层：应用层（HTTP、FTP、SMTP）、传输层（TCP、UDP）、互联网层（IP）和链路层（以太网）。DNS将域名转换为IP地址。分组交换将数据分解为独立传输的数据包。客户端‑服务器和对等网络是常见的网络模型。

4. Network Security | 网络安全

Threats include malware (viruses, worms, trojans), phishing, denial‑of‑service (DoS) attacks, and man‑in‑the‑middle attacks. Encryption protects confidentiality: symmetric encryption uses a single key; asymmetric encryption uses a public‑private key pair. Firewalls monitor and filter traffic. Penetration testing identifies vulnerabilities.

威胁包括恶意软件（病毒、蠕虫、木马）、网络钓鱼、拒绝服务（DoS）攻击和中间人攻击。加密保护机密性：对称加密使用单一密钥；非对称加密使用公钥‑私钥对。防火墙监控并过滤流量。渗透测试用于识别漏洞。

Authentication factors (something you know, have, are) strengthen access control. Policies such as regular updates, user training, and network forensics help maintain security. The Computer Misuse Act and GDPR are key legal frameworks.

身份认证因素（你知道的东西、你拥有的东西、你的生物特征）加强访问控制。定期更新、用户培训和网络取证等策略有助于维护安全。《计算机滥用法》和GDPR是重要的法律框架。

5. Databases & SQL | 数据库与SQL

A database is an organised collection of data. Relational databases use tables with rows (records) and columns (fields). Primary keys uniquely identify each record; foreign keys link tables. SQL (Structured Query Language) commands: SELECT … FROM … WHERE … ORDER BY. Data types include INTEGER, VARCHAR, DATE, BOOLEAN.

数据库是有组织的数据集合。关系型数据库使用具有行（记录）和列（字段）的表。主键唯一标识每条记录；外键连接表。SQL（结构化查询语言）命令：SELECT … FROM … WHERE … ORDER BY。数据类型包括INTEGER、VARCHAR、DATE、BOOLEAN。

Normalisation reduces data redundancy by organising tables to 3NF (Third Normal Form). DBMS software (e.g., MySQL, SQLite) manages the database. Indexes speed up queries. Data integrity is maintained through constraints (NOT NULL, UNIQUE, CHECK).

规范化通过将表组织到第三范式（3NF）来减少数据冗余。DBMS软件（如MySQL、SQLite）管理数据库。索引加速查询。数据完整性通过约束（NOT NULL、UNIQUE、CHECK）来维持。

6. Algorithms & Computational Thinking | 算法与计算思维

Computational thinking involves decomposition (breaking a problem down), pattern recognition, abstraction, and algorithm design. Algorithms are step‑by‑step instructions. Sorting algorithms include bubble sort, insertion sort, and merge sort. Searching algorithms: linear search (O(n)), binary search (O(log n) on sorted data).

计算思维包括分解（拆解问题）、模式识别、抽象和算法设计。算法是分步骤的指令。排序算法包括冒泡排序、插入排序和归并排序。搜索算法：线性搜索（O(n)），二分搜索（对已排序数据为O(log n)）。

Algorithm efficiency is expressed with Big O notation. Flowcharts and pseudocode are used to represent algorithms before coding. Trace tables help dry‑run code to identify logic errors. Recursion is a function calling itself, requiring a base case.

算法效率用大O符号表示。在编程前，用流程图和伪代码表示算法。跟踪表用于手工执行代码以识别逻辑错误。递归是函数调用自身，必须有基准情形。

7. Programming Concepts | 编程概念

Programming paradigms include procedural (sequence, selection with IF…ELSE, iteration with WHILE/FOR), object‑oriented (classes, objects, inheritance, encapsulation, polymorphism), and declarative. Variables have data types (integer, float, string, Boolean) and scope (local/global). Constants store fixed values.

编程范式包括面向过程（顺序，IF…ELSE选择，WHILE/FOR迭代）、面向对象（类、对象、继承、封装、多态）和声明式。变量有数据类型（整型、浮点型、字符串、布尔型）和作用域（局部/全局）。常量存储固定值。

Subroutines (procedures and functions) promote reusability. Parameter passing can be by value or by reference. Error handling uses try‑except blocks. IDEs provide editors, compilers/interpreters, and debugging tools. Testing (normal, boundary, erroneous data) ensures robustness.

子程序（过程和函数）提高可重用性。参数传递可以是传值或传引用。错误处理使用try‑except块。IDE提供编辑器、编译器/解释器和调试工具。测试（正常、边界、异常数据）确保程序的健壮性。

8. Data Structures | 数据结构

Arrays store elements of the same type in contiguous memory, accessed by index. Lists (or dynamic arrays) can grow. Stacks are LIFO (push, pop); queues are FIFO (enqueue, dequeue). Records group related fields of different types. Binary trees consist of nodes with up to two children; BST (Binary Search Tree) keeps left < root < right.

数组在连续内存中存储同类型元素，通过索引访问。列表（或动态数组）可增长。栈是后进先出（压栈、弹栈）；队列是先进先出（入队、出队）。记录将不同类型的相关字段组合在一起。二叉树由节点组成，每个节点最多有两个子节点；二叉搜索树（BST）保持左 < 根 < 右。

Hash tables use a hash function to compute an index, enabling fast lookups. Graphs consist of vertices and edges, used in social networks and shortest‑path algorithms. Understanding structure selection is crucial for efficient algorithms.

哈希表使用哈希函数计算索引，实现快速查找。图由顶点和边组成，用于社交网络和最短路径算法。理解结构的选择对于高效算法至关重要。

9. Boolean Logic & Logic Gates | 布尔逻辑与逻辑门

Boolean algebra uses TRUE (1) and FALSE (0). Basic logic gates: AND (∧), OR (∨), NOT (¬). Truth tables map all input combinations to outputs. Combined gates: NAND, NOR, XOR (⊕). Boolean expressions simplify using laws: De Morgan’s: ¬(A ∧ B) = ¬A ∨ ¬B.

布尔代数使用TRUE（1）和FALSE（0）。基本逻辑门：与（∧）、或（∨）、非（¬）。真值表将所有的输入组合映射到输出。组合门：与非、或非、异或（⊕）。布尔表达式可使用定律化简：德摩根律：¬(A ∧ B) = ¬A ∨ ¬B。

Logic circuits are built by connecting gates. Half adders and full adders perform binary addition. Flip‑flops store a single bit, forming the basis of registers and memory. These concepts underpin processor design.

逻辑电路通过连接逻辑门构建。半加器和全加器执行二进制加法。触发器存储单个位，构成寄存器和存储器的基础。这些概念是处理器设计的基石。

A XOR B = (A ∧ ¬B) ∨ (¬A ∧ B)

10. System Software & OS | 系统软件与操作系统

System software includes the operating system (OS), utilities, and translators (compiler, interpreter, assembler). The OS manages hardware, provides a user interface, handles multitasking, memory management, and peripheral management. Utility software performs maintenance tasks: disk defragmentation, backup, antivirus.

系统软件包括操作系统（OS）、实用工具和翻译器（编译器、解释器、汇编器）。操作系统管理硬件、提供用户界面、处理多任务、内存管理和外设管理。实用工具软件执行维护任务：磁盘碎片整理、备份、防病毒。

Low‑level languages (assembly) map directly to machine code; high‑level languages (Python, Java) are easier for humans. Compilers translate the whole program to machine code; interpreters translate and execute line by line. Virtual machines enable cross‑platform execution.

低级语言（汇编）直接映射到机器码；高级语言（Python、Java）对人类更友好。编译器将整个程序翻译为机器码；解释器逐行翻译并执行。虚拟机支持跨平台执行。

11. Ethical, Legal & Environmental Impact | 伦理、法律与环境影响

Digital technology raises ethical issues: privacy (data collection, CCTV), AI bias, automation and job loss, intellectual property. Legal frameworks like GDPR (data protection), the Computer Misuse Act (unauthorised access), and copyright law aim to protect individuals and organisations.

数字技术引发伦理问题：隐私（数据收集、闭路电视）、人工智能偏见、自动化与失业、知识产权。GDPR（数据保护）、《计算机滥用法》（未经授权访问）和版权法等法律框架旨在保护个人和组织。

Environmental concerns include e‑waste disposal, energy consumption of data centres, and the carbon footprint of manufacturing devices. Sustainable computing encourages recycling, energy‑efficient hardware, and virtual meetings. The digital divide highlights unequal access to technology globally.

环境问题包括电子废弃物处理、数据中心的能源消耗以及设备制造的碳足迹。可持续计算倡导回收、节能硬件和虚拟会议。数字鸿沟凸显全球技术接入不均。

12. Software Development Life Cycle | 软件开发生命周期

The SDLC phases: Analysis (requirements), Design (system architecture, UI mock‑ups, data structures), Implementation (coding), Testing (alpha, beta, acceptance), Evaluation, and Maintenance. Methodologies include waterfall (linear) and agile (iterative, e.g., Scrum). Prototyping helps clarify requirements early.

软件开发生命周期阶段：分析（需求）、设计（系统架构、UI模型、数据结构）、实现（编码）、测试（alpha、beta、验收）、评估和维护。方法学包括瀑布式（线性）和敏捷（迭代，如Scrum）。原型有助于在早期明确需求。

Version control (e.g., Git) tracks changes and facilitates collaboration. Documentation is created at each stage for users and developers. Successful projects balance time, cost, and quality constraints. Computational thinking is applied throughout the lifecycle.

版本控制（如Git）跟踪变更并促进协作。每个阶段都要为用户和开发人员创建文档。成功的项目需要在时间、成本和质量约束之间取得平衡。计算思维贯穿整个生命周期。

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IB & WJEC Computer Science: Mind Map Quick Revision | IB与WJEC计算机科学：思维导图速记