A1.3 · Computer fundamentals
A1.3 · 计算机基础
Functions of an Operating System
操作系统的功能
The role of the OS is carried out by a set of specific jobs: handing memory to programs, keeping files in order, driving the hardware, sharing the processor, guarding access and running the desktop, all while background work goes on unseen.
操作系统的作用是由一组具体的工作来完成的:把内存分给程序、把文件管好、驱动硬件、分享处理器、把关访问、运行桌面,而这一切都在后台工作悄然进行的同时发生。
Explainer
讲解
Function, not feature
功能,而不是特色
A1.3.1 covered the OS’s overall role. This statement is about the specific functions it performs to carry that role out. The guide names nine: memory management, the file system, device management, scheduling, security, accounting, the graphical user interface, virtualization and networking.
A1.3.1 讲的是操作系统总体的作用。本条陈述讲的是它为履行这一作用而执行的具体功能。学科指南列出了九项:内存管理、文件系统、设备管理、调度、安全、记账、图形用户界面、虚拟化和网络。
Running through all of them is one job: maintaining system integrity while background operations run. At any moment the OS is doing housekeeping the user never sees, updating caches, writing logs, checking devices, and it must do this without letting the visible programs break or interfere with each other.
贯穿所有这些功能的是一项工作:在后台操作运行的同时维护系统的完整性。任何时刻操作系统都在做用户看不见的杂务,比如更新缓存、写日志、检查设备,而它必须在做这些的同时,不让可见的程序崩溃或互相干扰。
Explainer
讲解
The nine functions
九项功能
| Function | What it does |
|---|---|
| Memory management | Allocates and reclaims RAM per process, keeps each process’s memory separate, and uses virtual memory (paging to disk) when RAM runs short |
| File system | Organises data into files and directories, tracks free space, and enforces naming and access rules |
| Device management | Uses device drivers to control hardware, and buffers, caches or spools data to smooth speed differences |
| Scheduling | Decides which ready process runs on the CPU next and for how long |
| Security | Authenticates users and checks permissions on every access; provides encryption and monitors for malware |
| Accounting | Tracks how much CPU time, memory, disk and network each user and process consumes, for auditing and billing |
| GUI | Provides windows, icons, menus and pointers so users can operate the machine visually |
| Virtualization | Runs several virtual machines on one physical machine through a hypervisor, isolating them from each other |
| Networking | Manages the network interface, assigns addresses and implements protocols so programs can communicate |
| 功能 | 它做什么 |
|---|---|
| 内存管理 | 为每个进程分配和回收 RAM,让各进程的内存彼此隔离,并在 RAM 不足时使用虚拟内存(把页换出到磁盘) |
| 文件系统 | 把数据组织成文件和目录,记录空闲空间,并强制执行命名和访问规则 |
| 设备管理 | 用设备驱动程序控制硬件,并通过缓冲、缓存或假脱机来抹平速度差异 |
| 调度 | 决定下一个由哪个就绪进程使用 CPU、用多久 |
| 安全 | 验证用户身份并在每次访问时检查权限;提供加密并监控恶意软件 |
| 记账 | 记录每个用户和进程消耗了多少 CPU 时间、内存、磁盘和网络,用于审计和计费 |
| GUI | 提供窗口、图标、菜单和指针,使用户能以可视化方式操作机器 |
| 虚拟化 | 通过管理程序在一台物理机上运行多个虚拟机,并让它们彼此隔离 |
| 网络 | 管理网络接口、分配地址并实现协议,使程序能够通信 |
Explore
探索
Each function in action
每项功能的实际运作
Pick a function to see one concrete thing it does and the effect a user would notice if it were missing.
选择一项功能,看看它具体做的一件事,以及如果缺少它用户会注意到的后果。
Check your understanding
检验你的理解
Virtual memory, where the OS moves less-used pages of RAM out to disk, is part of which function?
虚拟内存(操作系统把 RAM 中较少使用的页换出到磁盘)属于哪一项功能?
Common mistake
常见错误
RecurringTwo problems recur. First, answers name functions without describing them: “memory management, scheduling, security” is a list, not a description. Each needs a sentence saying what the OS actually does. Second, answers describe GUI features (windows, drag and drop) as if that were the whole OS; the GUI is one function of nine, and the important ones for most questions are memory, scheduling, files and devices.
反复出现有两个问题反复出现。第一,答案只是列出功能名称而不加描述:“内存管理、调度、安全”是清单,不是描述。每一项都需要一句话说明操作系统实际做了什么。第二,答案把 GUI 的特性(窗口、拖放)当成操作系统的全部来描述;GUI 只是九项功能之一,对多数题目而言更重要的是内存、调度、文件和设备。
Named, not described: “An operating system does memory management, file management, device management and scheduling.” Lists four labels with nothing said about any of them.
只点名,不描述: “操作系统负责内存管理、文件管理、设备管理和调度。”列了四个标签,却对任何一个都没有说明。
Described: “Memory management allocates a protected block of RAM to each process and pages less-used data to disk when RAM is full. Scheduling decides which waiting process runs on the CPU next. Device management uses drivers so programs can use any keyboard or printer through one interface. The file system stores data as named files in directories and tracks free disk space.”
有描述: “内存管理为每个进程分配一块受保护的 RAM,并在 RAM 满时把较少使用的数据换出到磁盘。调度决定下一个由哪个等待中的进程使用 CPU。设备管理借助驱动程序,使程序能通过统一接口使用任何键盘或打印机。文件系统把数据以命名文件的形式存放在目录中,并记录空闲磁盘空间。”
Revision questions
复习题
Specimen-paper style. Write an answer, then reveal the marking points and mark yourself.
采用样卷风格。写下答案,然后展开评分要点给自己打分。
[4]Describe four functions of an operating system.
[4]描述操作系统的四项功能。
Marking points
评分要点
- Any four, each with a sentence of what the OS does: memory management (protected blocks, virtual memory); file system (named files, free-space tracking); device management (drivers, buffering); scheduling (which process runs next); security (authentication, permissions); accounting; GUI; virtualization; networking.
- 以下任选四项,每项写一句操作系统做什么:内存管理(受保护的块、虚拟内存);文件系统(命名文件、空闲空间记录);设备管理(驱动程序、缓冲);调度(下一个运行哪个进程);安全(身份验证、权限);记账;GUI;虚拟化;网络。
[3]Describe how the memory-management function of an operating system uses virtual memory.
[3]描述操作系统的内存管理功能如何使用虚拟内存。
Marking points
评分要点
- When RAM is full, the OS moves less-used pages of memory out to disk.
- This frees RAM for the process that needs it now.
- When a paged-out page is needed again, it is brought back from disk (paging in).
- 当 RAM 已满时,操作系统把较少使用的内存页换出到磁盘。
- 这为当前需要内存的进程腾出 RAM。
- 当被换出的页再次被需要时,再从磁盘换回(换入)。
[4]Describe the file-system and device-management functions of an operating system.
[4]描述操作系统的文件系统功能和设备管理功能。
Marking points
评分要点
- File system: organises data as named files in a directory tree; tracks which disk blocks are free; enforces naming rules (no two files with one name in a folder).
- Device management: uses a driver per device so programs use a uniform interface; buffers/spools data to handle speed differences between the CPU and a slow device.
- 文件系统:把数据组织成目录树中的命名文件;记录哪些磁盘块空闲;强制执行命名规则(同一文件夹内不能有两个同名文件)。
- 设备管理:每个设备用一个驱动程序,使程序使用统一接口;通过缓冲 / 假脱机来处理 CPU 与慢速设备之间的速度差异。
[3]Describe what is meant by an operating system keeping the machine in a consistent, trustworthy state while its background tasks run.
[3]描述“操作系统在后台任务运行的同时,让机器保持一致、可信的状态”是什么意思。
Marking points
评分要点
- Background operations (updating caches, writing logs, checking devices) run continuously and unseen by the user.
- System integrity means the system stays correct and stable while they run.
- The OS must keep the visible programs isolated so background work does not corrupt their data or crash them.
- 后台操作(更新缓存、写日志、检查设备)持续运行,用户看不见。
- 系统完整性指的是在它们运行时系统保持正确和稳定。
- 操作系统必须让可见的程序保持隔离,使后台工作不会破坏它们的数据或让它们崩溃。
[4]Describe the accounting and security functions of an operating system.
[4]描述操作系统的记账功能和安全功能。
Marking points
评分要点
- Accounting: tracks how much CPU time, memory, disk and network each user and process uses; the data is used for auditing, finding bottlenecks and billing (e.g. cloud usage).
- Security: authenticates the user at login; checks permissions on every file/device/setting access; provides encryption and monitors for malware; keeps activity logs.
- 记账:记录每个用户和进程使用了多少 CPU 时间、内存、磁盘和网络;数据用于审计、找出瓶颈和计费(例如云使用量)。
- 安全:登录时验证用户;在每次访问文件 / 设备 / 设置时检查权限;提供加密并监控恶意软件;保留活动日志。
Flashcards
记忆卡片
Active recall for this statement’s key terms.
针对本条考纲陈述关键术语的主动回忆练习。
Keep this statement’s practice with you
把这条考纲陈述的练习保存下来
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免费账户:解锁 A1.3.2 以及所有其他 IB CS 2027 考纲陈述的每一道复习题,并同步你的学习进度。