Untitled Quiz

• Hardware includes the physical components of a computer system

Computer Architecture

• The CPU executes instructions and processes data in a computer application
• The CPU directly accesses memory
• The three main components of the CPU are the Arithmetic Logic Unit (ALU), the Control Unit (CU), and Registers
• A microprocessor is an integrated circuit on a single chip that performs a similar role to a CPU but on a smaller scale

Von Neumann Architecture and the Fetch-Decode-Execute Cycle

• Registers temporarily store data during processing, examples include PC, MDR, MAR, CIR, ACC
• A bus is a collection of wires that transmits data between computer components, examples include Address Bus, Data Bus and Control Bus

The Fetch Stage

• Input data stored in RAM or data from HDD is moved to RAM for processing
• Data is then moved from RAM to the CPU
• The Program Counter (PC), a component of the CPU, stores the address of the next instruction/data

Continued

• The address in the PC is sent to the Memory Address Register (MAR)
• The address travels from the PC to the MAR via the address bus
• The address is then sent to the Memory Data Register (MDR) using the data bus
• Once the MDR receives the instruction, it sends it to the Current Instruction Register (CIR) using the data bus
• The Current Instruction Register (CIR) is part of the Control Unit (CU), responsible for the next decoding stage

The Decode Stage

• Decoding begins when the Control Unit receives the instruction
• The Control Unit decodes the instruction using the instruction set
• It controls the flow of data within the CPU
• The Control Unit sends control signals to other components, instructing them on actions, such as read, write, add, or subtract
• It also controls the timing of operations, also known as the clock speed

The Execute Stage

• The Arithmetic Logic Unit (ALU) performs mathematical and logical operations on data and instructions
• The Accumulator (ACC), a special register within the ALU, stores interim calculation results before sending the final data to HDD or display

Key CPU Components

• Program Counter (PC): Stores the address of the next instruction to be processed
• Memory Address Register (MAR): Stores the address of the data to be processed
• Memory Data Register (MDR): Stores data fetched from memory
• Control Unit (CU): Controls the flow of data, and decodes and executes instructions
• Current Instruction Register (CIR): Stores the current instruction being decoded and executed
• Arithmetic Logic Unit (ALU): Performs arithmetic (+,-,*,/ shifting) or logic (AND, OR) operations
• Accumulator (ACC): Stores interim data during ALU calculations

CPU Busses

• Address Bus: Carries addresses throughout the computer system; unidirectional between CPU and memory
• Data Bus: Bidirectional, allowing data to be sent in both directions between CPU and memory and to/from input/output devices
• Control Bus: Bidirectional, carries control signals from the Control Unit (CU) to all other components

Core, Cache, and Clock Speed

• Number of Cores: CPUs with multiple cores (dual, quad) can perform multiple fetch-decode-execute cycles simultaneously, increasing performance
• Clock Speed: An internal clock controls the processing speed of instructions, modern computers have 2GHz clock speeds, processing 2 billion instructions per second
• Size of Cache: Cache stores frequently used instructions and data within the CPU, reducing the need to fetch from RAM and saving time

Instruction Set

• An instruction set is a set of all the commands a CPU can understand and process, these commands are in machine code which, once decoded, can be executed
• Instructions are decoded in sequence, with each operation instructing the ALU and CU on what task to perform - an operation consists of its opcode and operand

Opcode and Operand

• Opcode: Informs the CPU of the operation to be performed
• Operand: Specifies the data the operation will act on
• There is a limited number of opcodes a CPU can use known as the instruction set

Embedded Systems

• Embedded systems, unlike general-purpose computers (laptops, desktops), are designed for specific tasks, often using a built-in microcontroller
• Firmware provides basic machine instructions for hardware operation in embedded systems, traffic lights, washing machines, digital alarm clocks, and security systems are examples

Embedded System Features

• Built into a device
• Has a single, defined purpose
• Runs on firmware
• Does not have additional peripherals

Embedded System Advantages

• Low power consumption
• Small physical size
• Low cost to manufacture
• Can be controlled remotely
• Can operate in real-time and respond quickly to inputs

Input Devices

• Keyboard: Enters characters and functions into the computer by pressing buttons or keys
• Optical Mouse: A pointing device that uses an LED (light-emitting diode) to track movement
• Microphone: Translates sound vibrations into electronic signals
• Digital Camera: Uses an electronic image sensor to create photos and record video
• 2D Scanner: Makes digital copies of documents or pictures 3D Scanner: Analyzes real-world objects/environments to collect 3D data of shape and appearance

Bar Code Reader

• A barcode is a series of dark and light parallel lines of varying thicknesses that are read by a red laser
• Directs a beam of light across the bar code and measures the amount of light that is reflected back
• Dark lines reflect less light
• Light lines reflect more light
• Pattern is generated by reflected light and is converted to digital format
• Help supermarkets manage stock: scans product, looks it up in the database, deducts it from the system, alerts/reorders when stock is low, & updates inventory when new stock arrives

QR (Quick Response) Codes

• Is an advanced version of barcode
• Have squares instead of lines
• Use position and alignment markers for scanning; scannable by mobile camera app
• Black squares reflect less light, white squares reflect more light, which generate patterns that turn into digital format
• Three squares at the corner indicate data format (website, contact, email), while other small squares provide supportive data
• Have faster readability and greater storage capacity

Touch Screens

• Screens are sensitive to pressure for user interaction through touching pictures or words

Resistive Touch Screen Technology

• Uses multiple layers of material that transmit electric currents, the layers are separated by air or inert gas
• Touching the top layer presses it into the bottom layer, changing the electric current
• Contact point identified by voltage change

Resistive Benefits

• Easier technology
• Cheaper to manufacture
• Works with stylus/gloves

Resistive Drawbacks

• Poor visibility in sunlight
• Vulnerable to scratching

Capacitive Touch Screen Technology

• Sensors are located around the screen that are sensitive in electrical field changes
• Touching the screen with bare fingers changes the electrical field because the skin is a conductor of electricity
• Current is sent out from all four corners of the screen
• Touch location is calculated

Capacitive Benefits

• Good visibility in sunlight
• More longevity
• Faster response times

Capacitive Drawbacks

• Screen is easily shattered Screen is easily shattered
• Does not work with gloves

Infra Red / Surface Wave Touch Screen Technology

• An invisible grid on the screen with infrared sensors
• Sensors detect the "touch" when infrared beam is broken
• Touch position is calculated

Infra Red Benefits

• Good visibility in sunlight
• Can use stylus/gloves and faster response times

Infra Red Drawbacks

• Expensive
• Screen is easily shattered

Output Devices

• Actuatator: Converts energy into torque (rotational force), which moves a mechanisms

Output Devices and Their Descriptions

• Inkjet Printer: Produces hard copies of text or photos by spraying ink droplets onto paper
• Laser Printer: Uses laser technology and toner and produce high-quality output
• 3D Printer: Builds up layers, using powdered plastic, resin, and ceramic powder to produce solid objects
• Speaker: Converts electrical energy into acoustical signal energy (sound)
• LED Screen: Uses an array of Light Emitting Diodes (LEDs) as pixels with bright color, low power consumption, more longevity and are thin and light
• LCD Screen: Uses tiny liquid crystals; reduces glare/reflection, excellent image quality, color accuracy; also, has slower response times with limited color reproduction
• DLP Projector: Uses DMD (Digital Micromirror Device) chip and millions of micromirrors to determine the resolution of the image
• LCD Projector: Is an older technology than DLP projector

Memory Devices

• Primary memory, where data is stored for quick access, it is internal and directly accessible by the CPU; volatile and non-volatile

RAM (Random Access Memory)

• Is a volatile, temporary memory, that can be read
• Stores current user data and running software/operating system parts

ROM (Read Only Memory)

• Is non-volatile, permanent memory that cannot be altered
• Stores BIOS (Basic Input Output System)
• Stores start-up instructions

Storage Devices

• Secondary storage devices are non-volatile, holding data until it is deleted; internal or external, not directly accessible by the CPU, stores files/software

Comparing HDD and SDD

• HDD (Hard Disk Drive): magnetic storage, noisy, slower read/write, more read/write cycles, more moving parts, cheaper, higher power consumption, more heat, and greater longevity.
• SDD (Solid State Drive): Flash storage, quiet, faster R/W, less R/W cycles, no moving parts, expensive, less power, less heat, and takes less time to warm up

Types of Memory Devices

• Magnetic: HDD
• Optical: CD, DVD, Blu-Ray
• Flash: SSD, Pen Drive, USB

Magnetic Storage Devices

• Has more moving parts such as head, platter, and spindle
• The platter is a rotating disc divided into tracks and sectors
• Read/write heads move across the platter surface
• Data is read and written by electromagnets
• An electromagnet magnetizes dots to store data on each platter
• Magnetized dots store binary value 1, demagnetized stores 0, billions of these dots on each platter

Optical Storage Devices

• Data is represented by pits (0) and lands (1) on the surface
• Laser light is pointed at disk as it spins, reflected light captured by photoelectric cell
• When laser light hits pits, it doesn't reflect, storing the binary value 0
• When laser light hits lands, it reflects light and reads the binary value as 1

Flash Storage Devices

• Stores data by manipulating electrons within NAND or NOR chips, flashing the data onto the chip
• Contains cells and transistors laid out in a grid, wired together, intersections are the cells
• Data is stored as 0s and 1s in transistor withing semiconductor chip

Continued

• Electric current reaches the control gates and flows through to the floating gate for the data to be stored
• Transistors used as Control gate and floating gate
• When SSD is first created, all transistors are set to binary value 1; when data is stored they are 0

Virtual Memory

• Uses the hard disk or SSD when RAM becomes full, thus increasing memory
• If there is RAM shortage then virtual memory can occur, if several programs running can cause a system crash
• Partitions the hard drive to simulate RAM when RAM is full
• Oldest data transferred from RAM to HDD/SSD, allowing newer to be processed; when old data is needed, it is transferred back to RAM

Cloud Storage

• Cloud storage is a data storage on remote servers, stored on multiple servers, and is accessed through the internet
• Data is normally accessed through internet connection
• Instead of saving data on a local hard disk or other storage device, a user can save their data 'in the cloud'

The Benefits of Cloud Storage

• Files on the cloud can be accessed everywhere through any device at anytime
• No need to carry an external storage device
• Cloud accessed remotely
• Can be recovered in a hard disk failure
• Offers unlimited storage capacity

The Drawbacks of Cloud Storage

• Slow/unstable internet connections can cause problems accessing files
• Can be costly in large capacity
• If the cloud storage company fails, that is always possible

Sensors

• Input devices measure physical properties from surroundings, temperature, pressure, and acidity levels

List Of Sensors

• Gas: Detects gases (oxygen, carbon dioxide)
• Light: Uses photoelectric cells to measure brightness
• Infrared: Uses infrared beam, detects interruptions
• Pressure: Transducer that generates electric currents
• Temperature: Measures temperature changes
• Proximity: Detects nearby objects
• PH: Measures acidity ex, soil
• Magnetic field: Measures changes in magnetic fields
• Acoustic/sound: Microphones that convert sound into electric signals/pulses
• Accelerometer: Measures acceleration and motion

Sensor Applications

• Gas: monitor levels (greenhouse and car exhaust)
• Light: switch street lights or car headlights
• Infrared: wind screen wipers, rain
• Pressure: weighing of lorries
• Temperature: Monitor chemical process
• Proximity: Mobile screen switches off
• PH: Acidity levels
• Magnetic: Magnetic field intensity
• Acoustic/sound: Noises and vibrations
• Accelerometer: Airbag crash

Sensor Applicaitons Two

• Flow(rate) sensors: gas, and water pipes
• Level Sensors: liquid water in tanks, containers
• Moisture Measure: ex water in soils
• Humidity Measures: air

Network Hardware

• Network Interface Card (NIC) is to connect to the network that may be wired or wireless, or wireless NICs (WNICs) in modern configurations
• Media Access Control (MAC) address is used to identify a device
• MAC address is assigned by manufacturer and is never changed
• Every device has 12 digits alphanumeric
• First six digits is the id no of the manufacturer and the second half represents the identity of the device
• Hexadecimal numbers used as Millions of network devices are in existence used by every device

Router Hardware

• Hardware device that reads each data packet it receives, and send data packets to only its correct destination. Can connect to any location

IP (Internet Protocol) Address

• Uniquely identifies a device on a network, assigned by the network's Router; unique for given internet session, address is supplied when device connects to internet with two types, IPv4 and IPv6
• Can be dynamic or static- dynamic changes each time device is connected while static remains static

IPV4 vs IPV6

• IPV4: the "old" structure with 32-bits ex; 165.268.1.1, which contain 0 and 255, with four sets of numbers seperated by dots
• IPV6 is the "new" structure ex; 2001:0db8:0000, a hexadecimal value contains 128-bits 0000 and FFFF, and eight seets.

All Devices

• Every digital device needs a IP address to be connect to the internet