IB CCEA Computer Science: End-of-Term Revision Checklist | IB CCEA 计算机：期末复习提纲

📚 IB CCEA Computer Science: End-of-Term Revision Checklist | IB CCEA 计算机：期末复习提纲

As the end of term approaches, students following IB or CCEA Computer Science courses need a clear, structured revision plan. This checklist covers core topics common to both syllabi, from hardware fundamentals to ethical considerations, helping you consolidate key concepts and prepare effectively for your assessments.

期末考试临近，学习IB或CCEA计算机科学课程的学生需要一个清晰、结构化的复习计划。本提纲涵盖两个课程大纲共同的核心主题，从硬件基础到伦理考量，帮助你巩固关键概念，为评估做好充分准备。

1. Computer Architecture & Components | 计算机体系结构与组成

The CPU (Central Processing Unit) executes instructions via the fetch-decode-execute cycle, relying on the control unit (CU), arithmetic logic unit (ALU), and registers such as the program counter (PC) and accumulator (ACC).

CPU（中央处理器）通过取指-译码-执行周期运行指令，依赖于控制单元(CU)、算术逻辑单元(ALU)以及程序计数器(PC)和累加器(ACC)等寄存器。

Memory hierarchy balances speed, cost, and capacity: registers are fastest but smallest, followed by cache (L1/L2), RAM (main memory), and secondary storage like SSD/HDD.

存储器层次结构在速度、成本和容量之间取得平衡：寄存器最快但最小，其次是缓存(L1/L2)、RAM（主存）和SSD/HDD等辅助存储器。

Von Neumann architecture uses a single shared bus for data and instructions, while Harvard architecture separates them, enabling faster parallel access in embedded systems.

冯·诺依曼架构使用单一共享总线传输数据和指令，而哈佛架构将其分离，在嵌入式系统中可实现更快的并行访问。

The system bus consists of three lines: data bus (carries actual data), address bus (specifies memory locations), and control bus (transmits timing/command signals).

系统总线由三条线路组成：数据总线（承载实际数据）、地址总线（指定存储器地址）和控制总线（传输定时/命令信号）。

• Key revision: be able to label a CPU diagram and explain how clock speed, cores, and cache size impact performance.
• 复习重点：能标注CPU示意图，并解释主频、核心数和缓存大小对性能的影响。

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2. Data Representation | 数据表示

All data in a computer is stored as binary digits (bits). Unsigned integers use pure binary; for example, 1101₂ = (1 × 2³) + (1 × 2²) + (0 × 2¹) + (1 × 2⁰) = 13₁₀.

计算机中所有数据都以二进制位存储。无符号整数使用纯二进制；例如，1101₂ = (1 × 2³) + (1 × 2²) + (0 × 2¹) + (1 × 2⁰) = 13₁₀。

Hexadecimal (base-16) compacts binary: one hex digit represents four bits (nibble). The value A3₁₆ is 1010 0011₂ or 163₁₀.

十六进制（基数为16）用于压缩二进制：一个十六进制数字表示四个二进制位（半字节）。A3₁₆ 即 1010 0011₂ 或 163₁₀。

Negative numbers can be represented with sign-and-magnitude or two's complement. In two' omplement, -5 in 8-bit is calculated as invert 00000101 → 11111010, then add 1 → 11111011.

负数可用符号-数值或二进制补码表示。在8位二进制补码中，-5计算过程：将00000101取反得11111010，再加1得11111011。

Character encoding schemes include ASCII (7-bit, 128 characters) and Unicode (supports global scripts via UTF-8/16). UTF-8 is backward-compatible with ASCII and uses 1–4 bytes per character.

字符编码方案包括ASCII（7位，128个字符）和Unicode（通过UTF-8/16支持全球文字）。UTF-8向后兼容ASCII，每个字符使用1-4字节。

Real numbers are stored using floating-point representation (mantissa × 2^exponent). Normalisation maximises precision by adjusting the mantissa so its first bit is 1.

实数使用浮点表示法存储（尾数 × 2^指数）。规格化通过调整尾数使第一位为1，从而最大化精度。

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3. Computer Networks & the Internet | 计算机网络与互联网

A network allows devices (nodes) to share resources. LANs (Local Area Networks) cover a small geographic area, while WANs (Wide Area Networks) connect LANs across cities or countries.

网络允许设备（节点）共享资源。局域网(LAN)覆盖较小地理范围，广域网(WAN)则跨城市或国家连接多个局域网。

The TCP/IP protocol stack organises communication into four layers: Application (HTTP, FTP), Transport (TCP/UDP), Internet (IP), and Link/Network Interface. Each layer adds its own header to the data (encapsulation).

TCP/IP协议栈将通信组织为四层：应用层(HTTP、FTP)、传输层(TCP/UDP)、互联网层(IP)和链路/网络接口层。每一层为数据添加自己的报头（封装）。

IP addresses (IPv4: 32-bit dotted decimal, e.g., 192.168.1.1) identify hosts. Subnet masks distinguish the network and host portions. Routers use IP for packet forwarding between different networks.

IP地址（IPv4：32位点分十进制，如192.168.1.1）标识主机。子网掩码区分网络位和主机位。路由器使用IP在不同网络间转发数据包。

P (email), DNS (domain name → IP). HTTPS uses TLS/SSL encryption for secure communication.

关键协议：HTTP/HTTPS（网页）、FTP（文件传输）、SMTP/POP3/IMAP（电子邮件）、DNS（域名→IP）。HTTPS使用TLS/SSL加密实现安全通信。

Network topologies include star (central switch, easy troubleshooting), mesh (full or partial interconnect, high redundancy), and bus (single backbone, prone to collisions).

网络拓扑结构包括星型（中心交换机，易于排查故障）、网状（全互连或部分互连，高冗余）和总线型（单一主干，易发生碰撞）。

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4. Operating Systems & Resource Management | 操作系统与资源管理

The operating system (OS) acts as an intermediary between hardware and user applications, managing processor, memory, storage, and I/O devices.

操作系统(OS)充当硬件与用户应用程序之间的中介，管理处理器、内存、存储和I/O设备。

Memory management uses paging (dividing physical memory into fixed-size frames and processes into pages) or segmentation (variable-size logical units). Virtual memory allows execution of processes larger than RAM by swapping pages to/from disk.

内存管理使用分页（将物理内存划分为固定大小的帧，进程划分为页）或分段（可变大小的逻辑单元）。虚拟内存通过将页换入/换出磁盘，允许运行比RAM更大的进程。

Process scheduling ensures CPU time is shared fairly. Common algorithms: First-Come First-Served (FCFS), Shortest Job First (SJF), Round Robin (time slices), and Priority-based scheduling.

进程调度确保CPU时间公平分配。常见算法：先来先服务(FCFS)、最短作业优先(SJF)、轮转调度（时间片）和基于优先级的调度。

The OS handles interrupts by suspending the current process, saving its state, executing an interrupt service routine (ISR), and then restoring the original process.

操作系统处理中断的方式是：暂停当前进程，保存其状态，执行中断服务例程(ISR)，然后恢复原进程。

File systems organise data on secondary storage (e.g., NTFS, ext4, FAT32). They maintain a directory structure and manage free space, access permissions, and metadata such as timestamps.

文件系统在辅助存储器上组织数据（如NTFS、ext4、FAT32）。它们维护目录结构，管理空闲空间、访问权限和元数据（如时间戳）。

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5. Databases & Data Management | 数据库与数据管理

A relational database stores data in tables (relations) linked by primary keys and foreign keys. Each row is a record (tuple) and each column an attribute.

关系数据库将数据存储在表（关系）中，通过主键和外键关联。每一行是一条记录（元组），每一列是一个属性。

SQL (Structured Query Language) is used to define, manipulate, and query data. Basic commands: SELECT (retrieve), INSERT (add), UPDATE (modify), DELETE (remove).

SQL（结构化查询语言）用于定义、操纵和查询数据。基本命令：SELECT（检索）、INSERT（添加）、UPDATE（修改）、DELETE（删除）。

Normalisation reduces data redundancy. 1NF eliminates repeating groups; 2NF removes partial dependencies; 3NF eliminates transitive dependencies, ensuring each non-key attribute depends only on the primary key.

规范化减少数据冗余。第一范式消除重复组；第二范式去除部分依赖；第三范式消除传递依赖，确保每个非键属性只依赖于主键。

DBMS (Database Management System) provides concurrency control (locking), ACID properties (Atomicity, Consistency, Isolation, Durability) for transactions, and backup/recovery mechanisms.

数据库管理系统(DBMS)提供并发控制（锁定）、事务的ACID特性（原子性、一致性、隔离性、持久性）以及备份/恢复机制。

SQL Clause	Purpose	SQL 子句	用途
SELECT DISTINCT	Retrieve unique values	SELECT DISTINCT	检索不重复的值
WHERE	Filter rows	WHERE	过滤行
ORDER BY	Sort results	ORDER BY	对结果排序
JOIN	Combine rows from multiple tables	JOIN	连接多个表的行

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6. Algorithms & Problem Solving | 算法与问题解决

An algorithm is a step-by-step procedure to solve a problem. Key properties: finiteness, definiteness, inputs, outputs, and effectiveness.

算法是解决问题的分步过程。关键特性：有穷性、确定性、输入、输出和有效性。

Algorithm efficiency is expressed using Big O notation. O(1) is constant time, O(log n) logarithmic, O(n) linear, O(n²) quadratic. Quadratic algorithms can become impractical for large n.

算法效率用大O表示法表示。O(1)为常数时间，O(log n)对数时间，O(n)线性时间，O(n²)平方时间。对于较大的n，平方级算法可能变得不切实际。

Common searching algorithms: linear search (O(n), unsorted data) and binary search (O(log n), requires sorted data). Binary search repeatedly divides the search interval in half.

常见查找算法：线性搜索（O(n)，未排序数据）和二分搜索（O(log n)，要求数据已排序）。二分搜索反复将搜索区间减半。

Sorting algorithms: bubble sort (O(n²), simple but inefficient), insertion sort (O(n²), good for small/nearly sorted data), merge sort and quicksort (O(n log n) average). Merge sort uses a divide-and-conquer strategy.

排序算法：冒泡排序（O(n²)，简单但低效）、插入排序（O(n²)，适用于小规模或基本有序的数据）、归并排序和快速排序（平均O(n log n)）。归并排序采用分治策略。

Pseudocode and flowcharts are used to plan algorithms before coding. Flowchart symbols: oval (start/end), parallelogram (input/output), rectangle (process), diamond (decision).

伪代码和流程图用于在编码前规划算法。流程图符号：椭圆形（开始/结束）、平行四边形（输入/输出）、矩形（处理）、菱形（判断）。

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7. Programming Fundamentals | 编程基础

Variables store data; each has a name, data type (integer, real/float, Boolean, string, character), and a value. Constants are fixed values that cannot be changed during execution.

变量存储数据；每个变量有名称、数据类型（整型、实型/浮点型、布尔型、字符串、字符）和值。常量是在执行期间不可改变的固定值。

Control structures: sequence (default execution order), selection (if-else, switch/case), and iteration (while, for, repeat-until). Nested structures combine multiple control flow patterns.

控制结构：顺序（默认执行顺序）、选择（if-else、switch/case）和迭代（while、for、repeat-until）。嵌套结构组合多种控制流模式。

Functions/procedures promote modularity and code reuse. Parameters can be passed by value (a copy is made) or by reference (address of original variable is passed).

函数/过程促进模块化和代码重用。参数可按值传递（生成副本）或按引用传递（传递原变量的地址）。

Arrays store multiple elements of the same type in contiguous memory. A 1D array is a list; a 2D array resembles a table. Indexing typically starts at 0.

数组在连续内存中存储多个相同类型的元素。一维数组是列表；二维数组类似表格。索引通常从0开始。

Object-Oriented Programming (OOP) organises code into classes (blueprints) and objects (instances). Core OOP principles: encapsulation, inheritance, polymorphism, and abstraction.

面向对象编程(OOP)将代码组织为类（蓝图）和对象（实例）。核心OOP原则：封装、继承、多态和抽象。

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8. Software Development Lifecycle | 软件开发生命周期

→ testing → deployment → maintenance. Each phase must be completed before the next begins.

瀑布模型遵循线性顺序：需求分析→设计→实现→测试→部署→维护。每个阶段必须完成后才能开始下一阶段。

Agile development uses iterative cycles (sprints) with continuous feedback, allowing requirements to evolve. Extreme Programming (XP) and Scrum are popular agile frameworks.

敏捷开发采用迭代周期（冲刺）并结合持续反馈，允许需求演进。极限编程(XP)和Scrum是流行的敏捷框架。

Testing levels: unit testing (individual modules), integration testing (combined modules), system testing (whole system), and acceptance testing (user validation). Test data includes normal, boundary, and erroneous cases.

测试级别：单元测试（独立模块）、集成测试（组合模块）、系统测试（整个系统）和验收测试（用户验证）。测试数据包括正常、边界和错误用例。

Documentation includes internal (comments, code annotations) and external (user manuals, technical guides). Maintainability is improved by clear naming, modular design, and consistent style.

文档包括内部文档（注释、代码注解）和外部文档（用户手册、技术指南）。清晰的命名、模块化设计和统一风格可提高可维护性。

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9. Cybersecurity & Data Protection | 网络安全与数据保护

Common threats: malware (virus, worm, trojan), phishing (deceptive emails/sites), DoS/DDoS attacks (flooding services), SQL injection, and man-in-the-middle attacks.

常见威胁：恶意软件（病毒、蠕虫、木马）、网络钓鱼（欺骗性邮件/网站）、DoS/DDoS攻击（服务泛洪）、SQL注入和中间人攻击。

Encryption protects data confidentiality. Symmetric encryption uses a single shared key (e.g., AES); asymmetric encryption uses a public/private key pair (e.g., RSA). Digital signatures verify authenticity and integrity.

加密保护数据机密性。对称加密使用单一共享密钥（如AES）；非对称加密使用公钥/私钥对（如RSA）。数字签名验证真实性和完整性。

Firewalls filter incoming/outgoing traffic based on predetermined rules. Antivirus software detects and removes known malware using signature-based or heuristic analysis.

防火墙根据预定规则过滤传入/传出的流量。反病毒软件使用基于签名或启发式分析检测和清除已知恶意软件。

Authentication methods: what you know (passwords), what you have (tokens, smart cards), what you are (biometrics). Multi-factor authentication (MFA) combines two or more factors.

身份验证方法：你知道的（密码）、你拥有的（令牌、智能卡）、你本身的特征（生物识别）。多因素认证(MFA)结合两个或以上因素。

Data protection regulations (e.g., GDPR) require organisations to process personal data lawfully, fairly, and transparently, and to respect individuals' rights of access and erasure.

数据保护法规（如GDPR）要求组织合法、公正、透明地处理个人数据，并尊重个人的访问权和删除权。

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10. Ethical, Legal & Social Implications | 伦理、法律与社会影响

Computing professionals must adhere to ethical codes (e.g., ACM/IEEE) emphasising public interest, honesty, and fairness. Plagiarism and software piracy are legal and ethical violations.

计算机专业人员必须遵守强调公共利益、诚信和公平的道德规范（如ACM/IEEE）。剽窃和软件盗版是法律和伦理违规行为。

The digital divide refers to the gap between those who have access to digital technology and those who do not, influenced by economic, geographic, and educational factors.

数字鸿沟指拥有数字技术访问权的人群与没有的人群之间的差距，受经济、地理和教育因素影响。

Artificial intelligence raises ethical concerns: bias in training data, job displacement, accountability for autonomous decisions, and privacy invasion through surveillance.

人工智能引发伦理关切：训练数据中的偏见、工作岗位流失、自主决策的责任归属以及通过监视侵犯隐私。

Environmental impact of computing includes energy consumption of data centres, e-waste from discarded devices, and the carbon footprint of manufacturing and network infrastructure.

计算对环境的影响包括数据中心的能耗、废弃设备产生的电子垃圾以及制造和网络基础设施的碳足迹。

Intellectual property rights protect software through copyright, patents, and open-source licences. Understanding these helps developers choose appropriate licensing for their projects.

知识产权通过版权、专利和开源许可证保护软件。理解这些有助于开发者为项目选择合适的许可证。

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