slug
type
status
category
summary
date
tags
password
icon
 
 
Hardware: Computers and Their Components
 
A general-purpose computer system comprises a processor, memory, and I/O functionality. The following essential features are needed in a computer -
  • Input: Takes in data from the outside world.
  • Output: Displays data for human understanding.
  • Primary Storage: Main memory storing critical program instructions and data.
  • Secondary Storage: Non-volatile storage for noncritical data.
  • Removable secondary storage:
    • File backup and archives
    • Portable transfer of files to a second device
Embedded systems: Miniature computer systems such as microprocessors that are often a part of a more extensive system. Each embedded system performs a few specific functions, unlike general-purpose computers.
Benefits
Drawbacks
Reliable since there are no moving parts
Difficult to program functions since there is no interface
Require less power
Expensive expert help is needed for the repair
Cheap to mass-produce
ㅤ
Principle Operations of Hardware Devices
Laser printer: A laser beam and rotating mirrors are used to draw an image of the page on a photosensitive drum.
  • The image is converted into an electric charge, which attracts charged toner such that it sticks to the image.
  • Electrostatic-charged paper rolled against the drum.
  • Charge pulls toner away from drum and onto paper.
  • Heat applied in the fuser to fuse toner to the paper.
  • The electrical charge was removed from the drum, and excess toner was collected.
3D Printer:
  • The process starts with a saved digital file that holds the blueprint of the object to be printed.
  • The object is then built by sequentially adding layers of a material (e.g., polymer resin) until the object created.
  • The object is then cured (e.g., resin-made objects are hardened by UV light).
Microphone:
  • Incoming sound waves enter the screen and cause vibrations in the diaphragm.
  • Vibrations cause the coil to move past a magnetic core.
  • Electrical current is generated, which is then digitized.
Speaker:
  • Takes electrical signals and translates them into physical vibrations to create sound waves.
  • The electric current in the voice coil generates an electromagnetic field.
  • Change in digital audio signal causes current direction to change, which changes field polarity.
  • Electromagnet is either attracted or repelled to a permanent magnet, causing a diaphragm that is attached to the coil to vibrate.
  • Vibration transmitted to air in front of the speaker.
  • The degree of vibration determines the amplitude and frequency of the sound wave produced.
Magnetic Hard Disk:
  • Hard disks have platters whose surfaces are covered with a magnetisable material.
  • Platters are mounted on a central spindle and rotated at high speed.
  • The surface of platters is divided into concentric tracks & sectors, where data is encoded as magnetic patterns.
  • Each surface is accessed by read/write heads.
  • When writing, current variation in the head causes magnetic field variation on the disk.
  • When reading, magnetic field variation from the disk produces current variation in the read head.
Solid State (Flash) Memory:
  • Most use NAND-based flash memory.
  • Consist of a grid of columns & rows that has 2 transistors at each intersection.
  • Two transistors:
  • Floating Gate: stores electrons, and the presence or absence of charge (electrons) represents either 1 or 0.
  • Control Gate: controls charge (electrons) flow for read/write.
Optical Disc Reader/Writer:
  • The disc surface has a reflective metal layer and is spun.
  • The tracking mechanism moves the laser assembly.
  • The lens focuses laser onto the disc.
  • A laser beam shone onto a disc to read/write.
  • Tracks have sequences of amorphous and crystalline states on the metallic layer.
  • When reading, the reflected light from the different states on the track is encoded as bit patterns.
  • When writing, the laser changes surface to crystalline and amorphous states along the track, corresponding to 1s or 0s.
Touchscreen:
  • Considered as both an input & output device. There are two main-types:
  • Resistive: Consists of two charged plates made from materials that store electric charge. Pressure causes plates to touch, completing the circuit.
  • Capacitive: When touched, the charge is transferred to the finger. Point of contact registered with coordinates used to calculate the position.
Virtual (Reality) Headset:
  • Virtual headsets consist of 2 lenses, (an LCD) display, a circuit board with sensors, a cover and foam padding.
  • The display provides a simulation of a 3D environment generated by a 3D graphics package.
  • The user can ‘move’ in the virtual environment by moving their head or using controllers.
Buffers:
  • A queue that temporarily stores data to balance input/output speed of data, while the cache is the short-term memory storage that stores frequently used data.
Random Access Memory vs. Read-Only Memory
RAM
ROM
Volatile memory: loses content when power is turned off
Non-volatile memory: does not lose content when power is turned off
It can be read and altered
It can only be read
Used to store currently executing program
Used for storing OS kernel and boot-up instructions
Types of RAM - Static RAM vs. Dynamic RAM
SRAM
DRAM
Doesn’t need to refresh; hence, it uses less power and faster access time
Has to be refreshed; it has slower access times and needs higher power
More complex circuitry, hence more expensive
Only a single transistor & capacitor, hence less expensive to purchase
Each bit is stored in a flip-flop
Each bit is stored as a charge
Has lower data density
Has higher data density
Used in cache memory
Used in main memory
Types of ROM – PROM vs. EPROM vs. EEPROM
PROM
EPROM
EEPROM
Programmable ROM
Erasable Programmable ROM
Electrically Erasable Programmable ROM
It can be programmed only once after it is created
It can be erased by UV light exposure and can then be reprogrammed
It can be erased by an electrical signal and can then be reprogrammed
Data cannot be erased or deleted
Chip has to be removed for reprogramming
Can update data without removing the chip.
Monitoring and Control Systems
Monitoring System:
  • Monitors some state external to the computer system.
  • No changes were made to the environment by the system, and hence, no feedback.
Control System:
  • Regulates the behaviour of other devices or systems.
  • Event-driven system: the controller alters the system's state in response to some event.
  • Time-driven system, where the controller takes action at a specific point in time.
Hardware typically used in a system:
  • Sensor that measures an (analogue) property and transmits it to a processing unit, generally as an electrical or optical signal.
  • Actuators that switch on/off heavy appliances (e.g., heater to heat/fan to cool). ADC that converts analogue signals to digital signals. Transmission cable to transfer signals.
Feedback Systems:
  • Output from the system affects the input of sensors. Ensures the system operates within the given criteria.
  • Enabling the system output to affect subsequent system inputs may cause a change in the actions taken by the system.
  • This enables the system to adjust conditions in a continuous process automatically.

硬件：计算机及其组件

一个通用计算机系统包括处理器、内存和输入/输出功能。计算机需要以下基本功能：
  • 输入：从外部世界接收数据。
  • 输出：为人类理解显示数据。
  • 主存储：存储关键程序指令和数据的主内存。
  • 次级存储：非易失性存储非关键数据。
  • 可移动次级存储：
    • 文件备份和存档
    • 将文件便携式传输到第二个设备
嵌入式系统： 如微处理器之类的微型计算机系统，通常是更大系统的一部分。与通用计算机不同，每个嵌入式系统执行少数特定功能。
优点
缺点
可靠，因为没有移动部件
编程功能困难，因为没有接口
耗电少
修理需要昂贵的专家帮助
便宜的批量生产
ㅤ

硬件设备的基本操作

激光打印机：
  • 使用激光束和旋转镜子在感光鼓上绘制页面图像。
  • 图像转换为电荷，吸引带电的碳粉，使其粘附在图像上。
  • 静电带电的纸张滚动到鼓上。
  • 电荷将碳粉从鼓拉到纸上。
  • 在定影器中应用热量以将碳粉熔接到纸上。
  • 鼓上的电荷被移除，多余的碳粉被收集。
 
补充阅读：
A laser printer is a type of printer that uses a laser beam and toner to produce high-quality text and graphics on paper. Here’s how it typically works:
  1. Charging: A laser printer starts the printing process by charging a photosensitive drum with static electricity using a primary charge roller or corona wire.
  1. Exposing: A laser beam is then directed across the surface of the drum via rotating mirrors. This laser selectively discharges the drum, creating an electrostatic image of the page to be printed.
  1. Developing: Toner particles, which are electrically charged, are attracted to the image areas on the drum that were discharged by the laser.
  1. Transferring: The toner image on the drum is then transferred onto a piece of paper as it passes through the printer.
  1. Fusing: The paper with the toner is passed through heated rollers (the fuser unit). The heat and pressure from these rollers fuse the toner particles permanently into the fibers of the paper.
  1. Cleaning: After transferring the image, the drum is cleaned to remove any residual toner and recharged to prepare for the next print.
Laser printers are popular in both home and office environments due to their speed, precision, and capability to handle high volumes of print tasks more economically than inkjet printers over time.
 
激光打印机是一种使用激光束和碳粉在纸张上生成高质量文本和图形的打印机。以下是其典型的工作流程：
  1. 充电：激光打印机开始打印过程，通过初级充电辊或电晕丝对感光鼓进行静电充电。
  1. 曝光：通过旋转镜子，激光束被定向到鼓的表面。激光选择性地放电鼓，创建要打印页面的静电图像。
  1. 显影：碳粉颗粒带电后，被吸引到鼓上被激光放电的图像区域。
  1. 转印：鼓上的碳粉图像随后被转移到通过打印机传递的纸张上。
  1. 定影：带有碳粉的纸张通过加热滚筒（定影单元）。这些滚筒的热量和压力将碳粉颗粒永久地熔合到纸张的纤维中。
  1. 清洁：转印图像后，鼓被清洁以去除任何残留的碳粉，并重新充电，为下一次打印准备。
激光打印机因其速度、精度以及相比墨水喷射打印机能够更经济地处理大量打印任务而在家庭和办公环境中广受欢迎。
相关视频推荐：https://www.youtube.com/watch?v=WB0HnXcW8qQ
3D 打印机：
  • 过程从保存的数字文件开始，该文件包含要打印对象的蓝图。
  • 然后通过顺序添加材料层（例如聚合物树脂）来构建对象，直到创建对象。
  • 然后对对象进行固化（例如，树脂制成的对象通过紫外线硬化）。
 
麦克风：
  • 进来的声波进入屏幕并引起振膜的振动。
  • 振动使线圈在磁芯旁边移动。
  • 生成的电流随后被数字化。
补充阅读
The operational principle of a microphone is based on converting sound waves (mechanical energy) into electrical signals (electrical energy). Here’s how it works:
  1. Sound waves hit the diaphragm of the microphone, causing it to vibrate.
  1. These vibrations move a component (such as a coil or a capacitor) relative to a magnetic field or change the capacitance between plates.
  1. This motion induces a small electrical current or changes an electrical signal.
  1. The electrical signal is then amplified and transmitted as audio output.
Microphones typically operate on either dynamic (electromagnetic induction) or condenser (electrostatic principle) technologies.
麦克风的工作原理基于将声波（机械能）转换为电信号（电能）。具体步骤如下：
  1. 声波撞击麦克风的振膜，导致其振动。
  1. 这些振动使一个部件（如线圈或电容器）相对于磁场移动，或改变电容器板之间的电容。
  1. 这种运动在磁场中产生微弱的电流或改变电信号。
  1. 该电信号经过放大后，作为音频输出传输。
麦克风通常基于动圈式（电磁感应原理）或电容式（静电原理）技术工作。
相关视频推荐：https://youtu.be/vRmEeNNXSfk?t=14
 
扬声器：
  • 接收电信号并将其转换为物理振动以产生声波。
  • 语音线圈中的电流产生电磁场。
  • 数字音频信号的变化导致电流方向变化，从而改变场极性。
  • 电磁铁被永磁体吸引或排斥，导致与线圈相连的振膜振动。
  • 振动传递到扬声器前的空气中。
  • 振动的程度决定声波产生的幅度和频率。
补充阅读：
The operational principle of a speaker is based on the conversion of electrical energy into sound waves through electromagnetic induction. Here's how it works:
  1. Electrical Signal: The speaker receives an electrical audio signal from a source, which represents sound in the form of alternating current (AC).
  1. Electromagnetic Induction: Inside the speaker, there is a coil of wire (called the voice coil) placed in the magnetic field of a permanent magnet. When the electrical signal passes through the coil, it creates a fluctuating electromagnetic field.
  1. Vibration: The fluctuating magnetic field causes the voice coil to move back and forth rapidly. The coil is attached to a diaphragm, usually made of a lightweight material like paper or plastic.
  1. Sound Waves: As the diaphragm moves, it pushes and pulls the surrounding air, creating pressure waves. These pressure waves are what we perceive as sound.
In summary, a speaker works by using electromagnetic forces to move a diaphragm that generates sound waves corresponding to the electrical signal it's fed.
扬声器的工作原理基于通过电磁感应将电能转换为声波。具体过程如下：
  1. 电信号：扬声器从音源接收电音频信号，该信号以交流电（AC）的形式代表声音。
  1. 电磁感应：扬声器内部有一个线圈（称为音圈），它放置在永久磁铁的磁场中。当电信号通过音圈时，会产生一个变化的电磁场。
  1. 振动：变化的电磁场导致音圈快速地来回移动。音圈连接着一个通常由轻质材料（如纸或塑料）制成的振膜。
  1. 声波：随着振膜的移动，它推动或拉动周围的空气，产生压力波。这些压力波就是我们感知到的声音。
总的来说，扬声器通过电磁力驱动振膜运动，进而生成与输入电信号对应的声波。
 
相关视频推荐：https://www.youtube.com/watch?v=5yNFiki5TBg

磁盘硬盘：

  • 硬盘具有表面覆盖有可磁化材料的磁盘。
  • 磁盘安装在中心主轴上，并以高速旋转。
  • 磁盘表面被划分为同心轨道和扇区，在这些区域中，数据以磁性模式编码。
  • 每个表面由读写头访问。
  • 写入时，头部中的电流变化导致磁盘上的磁场变化。
  • 读取时，磁盘上的磁场变化在读取头中产生电流变化。
相关视频推荐：https://www.youtube.com/watch?v=wteUW2sL7bc

固态（闪存）内存：

  • 大多数使用基于 NAND 的闪存内存。
  • 包含有交叉列和行的网格，每个交叉点有两个晶体管。
    • 浮动门：存储电子，电子的存在与否代表 1 或 0。
    • 控制门：控制读写时的电子流。
相关视频推荐：https://www.youtube.com/watch?v=5Mh3o886qpg&t=88s

光盘读写器：

  • 光盘表面有一个反射金属层，并且被旋转。
  • 跟踪机制移动激光组件。
  • 透镜将激光聚焦到光盘上。
  • 用激光束照射光盘进行读写。
  • 轨道具有金属层上无定形和晶态的状态序列。
  • 读取时，来自轨道上不同状态的反射光被编码为比特模式。
  • 写入时，激光改变表面至晶态和无定形状态，对应于 1 或 0。
相关视频推荐：https://www.youtube.com/watch?v=H-jxTzFrnpg

触摸屏：

  • 视为输入和输出设备。
  • 两种主要类型：电阻式和电容式。
    • 由两个带电的板组成。
    • 由存储电荷的材料制成。
    • 压力使板接触，完成电路。
    • 触摸时，电荷传递给手指。
    • 接触点注册，使用坐标计算位置。

虚拟（现实）头盔：

  • 虚拟头盔包含两个镜片、一个（液晶）显示屏、一个带传感器的电路板、一个盖子和泡沫垫。
  • 显示屏提供由 3D 图形包生成的 3D 环境的模拟。
  • 用户可以通过移动头部或使用控制器在虚拟环境中“移动”。

缓冲器和缓存：

  • 缓冲器是一个临时存储数据的队列，用来平衡数据的输入/输出速度，而缓存是存储频繁使用数据的短期内存存储。

随机访问内存与只读内存：

RAM（随机访问内存） 与 ROM（只读内存）：
  • RAM：挥发性内存，断电时内容丢失。
  • ROM：非挥发性内存，断电时内容不丢失。
  • RAM 用于存储当前执行的程序。
  • ROM 用于存储操作系统内核和启动指令。

静态 RAM 与动态 RAM：

SRAM（静态 RAM） 与 DRAM（动态 RAM）：
  • SRAM 不需要刷新，因此使用电力较少，访问时间更快。
  • DRAM 需要刷新，访问时间较慢，需要更多电力。
  • SRAM 电路更复杂，因此更昂贵。
  • DRAM 只使用一个晶体管和一个电容，因此购买成本较低。
  • SRAM 用于缓存内存，DRAM 用于主内存。

可编程 ROM、可擦写可编程 ROM 与电可擦写可编程 ROM：

PROM（可编程 ROM）、EPROM（可擦写可编程 ROM） 与 EEPROM（电可擦写可编程 ROM）：
  • PROM 在生产后只能编程一次。
  • EPROM 可通过紫外线曝光擦除后重新编程。
  • EEPROM 可通过电信号擦除并重新编程。

监控与控制系统：

监控系统：
  • 监控计算机系统外部的某种状态。
  • 系统对环境没有任何改变，因此没有反馈。
控制系统：
  • 调节其他设备或系统的行为。
  • 事件驱动系统：控制器响应某些事件改变系统状态。
  • 时间驱动系统：控制器在特定时间点采取行动。

硬件反馈系统：

  • 系统的输出影响传感器的输入。
  • 确保系统在给定标准内操作。
  • 系统输出能影响随后的系统输入，可能导致系统采取的行动发生变化。
  • 这使得系统能自动调整条件，进行持续的过程调整。
How does computer hardware workTests for CIE 9618
Loading...