📚 IGCSE CCEA Computer Science: Mind Map Quick Memorisation | IGCSE CCEA 计算机：思维导图速记
This revision series provides a rapid, mind‑map style overview of the entire IGCSE CCEA Computer Science syllabus. We break each topic into a concise English paragraph followed immediately by its Chinese equivalent, helping you to memorise key concepts and definitions efficiently. Use these paired paragraphs to build your own visual mind maps and recall the material quickly in your exam.
本复习系列以思维导图风格全面概览 IGCSE CCEA 计算机科学考纲。我们将每个主题分解为简明的英文段落，紧接其后的是对应的中文段落，帮助你高效记忆关键概念和定义。你可以利用这些配对段落创建自己的视觉思维导图，从而在考试中快速回忆相关内容。
1. Number Systems and Conversions | 数字系统与转换
Denary, binary and hexadecimal are the three core number systems. Denary (base‑10) uses digits 0–9; binary (base‑2) uses 0 and 1; hexadecimal (base‑16) uses 0–9 and A–F. To convert denary to binary, repeatedly divide by 2 and record the remainders. Binary to hexadecimal groups bits in fours from the right, then converts each group to its hex equivalent. Understanding these conversions is essential for data representation, memory addressing, and colour codes in computing. Always check your binary addition and overflow when the result exceeds the bit width.
十进制、二进制和十六进制是三种核心数字系统。十进制（基数为10）使用数字0–9；二进制（基数为2）使用0和1；十六进制（基数为16）使用0–9和A–F。将十进制转换为二进制时，反复除以2并记录余数。二进制转十六进制时，从右往左每四位一组，再将每组转换为对应的十六进制符号。理解这些转换对数据表示、内存寻址和计算机中的颜色代码至关重要。当结果超出位宽时，一定要检查二进制加法及溢出。
2. Data Storage: Bits, Bytes and Units | 数据存储：位、字节及单位
Bit is the smallest unit of data (0 or 1). Byte , tebibyte (TiB = 2⁴⁰). Alternatively, kilobyte (kB = 10³ bytes) is used in some contexts. File sizes econds) × channels. Image file size = width × height × colour depth (bits). Data compression (lossy and lossless) reduces file size but may affect quality.
位是数据的最小单位（0或1）。字节由8位组成，通常用于存储一个字符。更大的单位遵循2的幂次：kibibyte（KiB = 2¹⁰ 字节）、mebibyte（MiB = 2²⁰）、gibibyte（GiB = 2³⁰）、tebibyte（TiB = 2⁴⁰）。在某些语境下也会使用 kilobyte（kB = 10³ 字节）。图像、声音和视频的文件大小取决于分辨率、色彩深度、采样率和位深度。声音文件大小 = 采样率 × 位深度 × 时长（秒） × 声道数。图像文件大小 = 宽 × 高 × 色彩深度（位）。数据压缩（有损和无损）可减小文件体积，但可能影响质量。
3. Computer Architecture: CPU and Memory | 计算机体系结构：CPU 与存储器
The Central Processing Unit (CPU) contains the arithmetic logic unit (ALU), control unit (CU), and registers (PC, MAR, MDR, CIR, ACC). It follows the fetch‑decode‑execute cycle in PC → MAR, instruction to MDR), decode it (CIR), then execute (ALU performs operation). Cache is high‑speed memory inside the CPU. RAM (volatile) holds active programs and data; ROM (non‑volatile) stores firmware like BIOS. Clock speed (measured in GHz) and cores affect performance. Embedded systems have a dedicated microprocessor with limited memory on a single chip.
中央处理器（CPU）包含算术逻辑单元（ALU）、控制单元（CU）和寄存器（PC、MAR、MDR、CIR、ACC）。它遵循取指‑译码‑执行周期：从内存取指令（PC中的地址 → MAR，指令 → MDR），译码（CIR），然后执行（ALU 执行操作）。缓存是CPU内部的高速存储器。RAM（易失）存储正在运行的程序和数据；ROM（非易失）存储固件如 BIOS。时钟速度（以GHz为单位）和内核数量影响性能。嵌入式系统在一个芯片上集成专用微处理器和有限内存。
4. Input and Output Devices | 输入与输出设备
Input devices include keyboard, mouse, touchscreen, microphone, barcode scanner, sensors (temperature, light, pressure), and digital camera. They translate human actions or physical conditions into machine‑readable signals. Output devices include monitor (LCD, LED), printer (inkjet, laser), speaker, and actuator (motor, pump). Touchscreen acts as both input and output. The choice of device depends on factors like speed, resolution, cost, environment, and user requirements. Automatic data capture (ADC) methods reduce errors and speed up processes, e.g. barcode readers in retail, sensors in automatic doors.
输入设备包括键盘、鼠标、触摸屏、麦克风、条形码扫描器、传感器（温度、光线、压力）和数码相机。它们将人的操作或物理条件转换为机器可读取的信号。输出设备包括显示器（LCD、LED）、打印机（喷墨、激光）、扬声器和执行器（电机、泵）。触摸屏同时作为输入和输出设备。设备的选择取决于速度、分辨率、成本、环境和用户需求等因素。自动数据采集（ADC）方法可减少错误并加快处理速度，例如零售业中的条形码阅读器、自动门中的传感器。
5. Software: System and Application | 软件：系统软件与应用软件
System software includes operating systems (Windows, Linux, iOS), utility programs (antivirus, backup, disk defragmenter), and language translators (compiler, interpreter, assembler). The OS manages hardware, provides a user interface, handles multitasking, and controls security. Application software performs specific tasks for users: word processors, spreadsheets, databases, web browsers, and graphics editors. High‑level languages like Python are easier to read and write but need translation; low‑level languages (assembly, machine code) are closer to hardware. Understand the difference between proprietary, open source, and shareware software.
系统软件包括操作系统（Windows、Linux、iOS）、实用程序（杀毒、备份、磁盘碎片整理）和语言翻译器（编译器、解释器、汇编器）。操作系统管理硬件，提供用户界面，处理多任务并控制安全性。应用软件为用户执行特定任务：文字处理、电子表格、数据库、网络浏览器和图形编辑器。高级语言（如 Python）更易读写，但需要翻译；低级语言（汇编语言、机器码）更接近硬件。要理解专有软件、开源软件和共享软件之间的区别。
6. Networks: Topologies and Protocols | 网络：拓扑与协议
LAN (Local Area Network) covers a small area; WAN (Wide Area Network) spans large distances. Star topology connects all nodes to a central switch – if one cable fails, only that node is affected, but the switch is a single point of failure. Mesh topology offers redundancy with multiple connections, used in the Internet. Protocols are sets of rules: TCP/IP (transmission), HTTP/HTTPS (web), FTP (file transfer), SMTP (email sending), POP3/IMAP (email receiving). Network hardware includes router, switch, NIC, WAP, and transmission media (copper, fibre optic, wireless). Bandwidth is measured in bits per second (bps).
局域网（LAN）覆盖较小区域；广域网（WAN）跨越长距离。星型拓扑将所有节点连接到中央交换机——如果某根电缆出故障，只有该节点受影响，但交换机是单点故障。网状拓扑通过多条连接提供冗余，用于互联网。协议是一套规则：TCP/IP（传输）、HTTP/HTTPS（网页）、FTP（文件传输）、SMTP（邮件发送）、POP3/IMAP（邮件接收）。网络硬件包括路由器、交换机、网卡、无线接入点和传输介质（铜缆、光纤、无线）。带宽以比特每秒（bps）为单位测量。
7. Database Fundamentals | 数据库基础
A database is a structured collection of data. Tables hold records (rows) and fields (columns). Each table has a primary key that uniquely identifies records; foreign keys link tables in a relational database. SQL (Structured Query Language) is used to define, query, update, and manage data. Basic commands: SELECT, FROM, WHERE, ORDER BY, INSERT INTO, UPDATE, DELETE. Data validation (range check, presence check, format check) ensures input accuracy. DBMS (Database Management System) controls access, security and integrity. Normalisation reduces data redundancy and improves consistency.
数据库是结构化的数据集合。表包含记录（行）和字段（列）。每个表都有一个主键唯一标识记录；外键在关系数据库中连接表。SQL（结构化查询语言）用于定义、查询、更新和管理数据。基本命令：SELECT、FROM、WHERE、ORDER BY、INSERT INTO、UPDATE、DELETE。数据验证（范围检查、存在检查、格式检查）确保输入准确。数据库管理系统（DBMS）控制访问、安全性和完整性。规范化减少数据冗余并提高一致性。
8. Algorithms, Flowcharts and Pseudocode | 算法、流程图与伪代码
Algorithms are step‑by‑step procedures to solve problems. They can be expressed in flowcharts al = start/stop, rectangle = process, diamond = decision, parallelogram = input/output) or pseudocode. Key constructs: sequence, selection (IF‑THEN‑ELSE), and iteration (FOR, WHILE, REPEAT‑UNTIL). Array is a data structure holding multiple values of the same type, accessed by index. Searching algorithms include linear search (O(n)) and binary search (O(log n), requires sorted data). Sorting algorithms: bubble sort (O(n²)), insertion sort, merge sort (O(n log n)). Trace tables help debug logic.
算法是解决一个问题的逐步过程。它们可以用流程图（椭圆 = 开始/结束，矩形 = 处理，菱形 = 判断，平行四边形 = 输入/输出）或伪代码来表达。关键结构：顺序、选择（IF‑THEN‑ELSE）和迭代（FOR, WHILE, REPEAT‑UNTIL）。数组是一种数据结构，存储同一类型的多个值，通过索引访问。搜索算法包括线性搜索（O(n)）和二分搜索（O(log n)，要求数据已排序）。排序算法：冒泡排序（O(n²)）、插入排序、归并排序（O(n log n)）。跟踪表有助于调试逻辑。
9. Logic Gates and Boolean Algebra | 逻辑门与布尔代数
Logic gates form the building blocks of digital circuits. The basic gates are NOT (inverter), AND (output 1 only if both inputs are 1), OR (output 1 if at least one input is 1), NAND (AND followed by NOT), NOR (OR followed by NOT), and XOR (output 1 if inputs are different). Truth tables show all possible input combinations and outputs. Boolean algebra mplifies logic expressions. Combinational circuits combine gates to perform arithmetic (half adder, full adder).
逻辑门构成数字电路的基本构建块。基本门包括非门（反相器）、与门（仅在两个输入同为1时输出1）、或门（至少一个输入为1时输出1）、与非门（与门后接非门）、或非门（或门后接非门）和异或门（输入不同时输出1）。真值表显示所有可能的输入组合及输出。布尔代数（使用像德摩根定理的定律：(A · B)′ = A′ + B′ 和 (A + B)′ = A′ · B′）简化逻辑表达式。组合电路将门组合起来执行算术运算（半加器、全加器）。
10. Cybersecurity Threats and Prevention | 网络安全威胁与防护
Malware: virus (attaches to files), worm (self‑replicating across networks), Trojan horse (disguised as legitimate software), spyware (records keystrokes), ransomware (encrypts data). Social engineering tricks users into revealing information: phishing (fake emails), pharming (redirecting websites), blagging (pretexting). Brute‑force attacks guess passwords repeatedly. Preventive measures: firewalls (filter traffic), encryption (SSL/TLS), anti‑malware software, penetration testing, user access levels, strong password policies, regular updates, and staff training. Data destruction methods: shredding, degaussing, overwriting.
恶意软件：病毒（附着于文件）、蠕虫（在网络中自我复制）、特洛伊木马（伪装成合法软件）、间谍软件（记录击键）、勒索软件（加密数据）。社会工程学欺骗用户泄露信息：网络钓鱼（虚假邮件）、网址嫁接（重定向网站）、假冒诈骗（托辞诈骗）。暴力破解攻击不断尝试猜测密码。预防措施：防火墙（过滤流量）、加密（SSL/TLS）、反恶意软件、渗透测试、用户访问级别、强密码策略、定期更新和员工培训。数据销毁方法：粉碎、消磁、覆盖。
11. Ethical, Legal and Environmental Issues | 伦理、法律与环境问题
The Data Protection Act requires that personal data be processed fairly, lawfully, and securely, and not kept longer than necessary. Computer Misuse Act makes unauthorised access, modification or creation of malware a criminal offence. Copyright, Designs and Patents Act protects software intellectual property. Freedom of Information Act gives access to public body information. Environmental impact includes energy consumption of data centres, e‑waste, and the use of hazardous materials. Green computing promotes energy‑efficient hardware, virtualisation, and responsible recycling. AI ethics deals with bias, accountability, and job automation.
数据保护法要求个人数据必须公平、合法、安全地处理，且保存时间不超过必要期限。计算机滥用法将未经授权的访问、修改或创建恶意软件定为刑事犯罪。版权、外观设计和专利法保护软件知识产权。信息自由法给予公众获取公共机构信息的权利。环境影响包括数据中心的能源消耗、电子废弃物以及有害材料的使用。绿色计算提倡节能硬件、虚拟化和负责任的回收。人工智能伦理涉及偏见、问责制和工作自动化问题。
12. Programming Concepts and Testing | 编程概念与测试
Variables and constants store data; data types include integer, real, Boolean, character, string. Selection statements: IF, ELSE, ELSE IF, CASE/SWITCH. Iteration: count‑controlled loops (FOR) and condition‑controlled loops (WHILE, DO‑WHILE). Subprograms (functions and procedures) promote modularity. Scope defines where a variable is accessible (local or global). Testing uses normal, boundary (edge), and erroneous data. Test tables document expected vs actual outcomes. Debugging techniques: dry runs, trace tables, breakpoints. IDEs provide an editor, compiler/interpreter, debugger, and auto‑completion in an integrated environment.
变量与常量存储数据；数据类型包括整型、实型、布尔型、字符、字符串。选择语句：IF、ELSE、ELSE IF、CASE/SWITCH。迭代：计数控制循环（FOR）和条件控制循环（WHILE、DO‑WHILE）。子程序（函数和过程）促进模块化。作用域定义变量可访问的范围（局部或全局）。测试使用正常数据、边界（边缘）数据和错误数据。测试表记录预期与实际结果。调试技术：手工执行、跟踪表、断点。集成开发环境（IDE）在一个集成环境中提供编辑器、编译器/解释器、调试器和自动补全功能。
Published by TutorHao | IGCSE CCEA 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