Computer Science Chapter 3

CPU

A component in the computer used to process data and instructions from RAM

Microprocessor

an integrated circuit than is multi-fuctional

Embedded system

a specific computer system dedicated to one task

Architecture

A design of a computer

Von neumann architecture

allow main memory to both store data and instructions in the same place

Register

High speed memory

Cache

< registers speed

Clock speed

Number of Fetch-Execute-Decode cycles can be executed per second (Measured in GHz)

Clock speed effect

As you increase the clock speed,the more instructions can be processed my the CP

Cache Size & Speed

Small, fast memory on the integrated cicuit of the CPU. Used as temporary storage and quick access to frequently executed instructions and fetched data

Cache Size & Speed effect

As cache size and speed increase: The more instructions can be stored and executed and retrieved later , reducing the time for one Fetch- Execute- Decode cycle

Core

Each core is like a copy of a CPU that has its own - CO, ALU, ACC ,General use Registers

Core effect

This means that the core can multi task and multiple instructions can be processed at once

Buses

Parallel wires in a computer circuit that connect component together

Instruction sets

Lists of all comands a CPU could used and be processed through machine language

Opcode

The operation code indicates what function should be performed

Opcode examples

ADD,SUB,LDA,STA,HLT

Operand

The location where the operation takes place

Operand examples

Just some random binary numbers

Embedded system characteristics

A computer system with a specific function + Small + less power + lower cost

Input

Put simply it is the hardware tangible that could be connected that is used to interact with the system, by inputting certan instructions and commands to the system then it is processed and produce an output

Barcode Scanner

Reads barcodes to capture product information Quickly and accurately retrieves product details for stock and checkout

Digital Camera

Captures photographs or videos as digital images High-quality visual content

Keyboard

Inputs text and commands by pressing keys Type documents Enter data Control software

Microphone

Captures analogue sound and converts it into digital signals Audio recording Voice communication

Optical Mouse

Moves the cursor on the screen based on hand movements over a surface Precise control and navigation on a computer screen

QR Code Scanner

Reads QR codes to access stored information Quickly retrieves data from QR codes Website links or product information

Touch Screen (Resistive)

Detects touch by pressing a flexible screen layer Direct interaction with the device

Touch Screen (Infra-red)

Detects touch by interrupting infrared light beams across the screen Accurate touch detection Works well in various lighting conditions

Touch Screen (Capacitive)

Detects touch through changes in electrical charge on the screen surface Smooth, responsive touch experience with multi-touch capabilities

Two-Dimensional (2D) Scanner

Captures flat, 2D images of documents or photos Digitises documents and photos for storage, editing, or sharing

Three-Dimensional (3D) Scanner

Captures detailed 3D shapes and dimensions of objects Creates digital models of objects for design, analysis, or reproduction

Output

hardware components that are also tangible and use the "machine language" they received to an understandable to human format that not only represent text but also images, colours and much more forms

Actuator

Converts energy into motion Makes things move Performs physical tasks based on instructions from a computer or control system

Digital Light Processing (DLP) projector

Projects images onto a screen Shows images or video by shining light through tiny mirrors High-quality images

Inkjet printer

Prints text and images onto paper by spraying tiny droplets of ink Low cost compared to other types of printer

Laser printer

Heat from a laser fuses toner (fine powder) onto paper High-quality prints Fast print speed

Light Emitting Diode (LED) screen

Displays images and video using tiny lights called LEDs High-quality images Bright Energy efficient Thin

Liquid Crystal Display (LCD) projector

Projects images or video onto a screen by shining light through liquid crystal panels Bright Excellent balance of quality and affordability

Liquid Crystal Display (LCD) screen

Displays images and video using liquid crystals with a backlight Energy efficient Thin Sharp images Lightweight

Speaker

Converts electrical signals into analogue sound waves to play music Multiple shapes and sizes

3D printer

Adds thin layers of plastic, one on top of another to form a three dimensional object Create prototypes Custom parts

Sensors

Measure and detects the surrounding environment

Acoustic sensor

Sound levels To detect changes in sound levels of industrial machinery To monitor noise pollution In security system to detect suspicious sounds

Accelerometer sensor

Acceleration rate, tilt, vibration Detecting sudden changes in vehicle movement and deploy safety features if needed In mobile phones to detect orientation of the device

Flow sensor

Rate of gas, liquid or powder flow Detect changes in the flow through pipes in water system

Gas sensor

Presence of a gas e.g. carbon monoxide Detect levels of gas in confined spaces Detect gas levels when fixing gas leaks

Humidity sensor

Levels of water vapour Monitor humidity in greenhouses

Infra-red sensor

Detecting motion or a heat source Security systems detecting intruders who break the beam Measures heat radiation of objects - used by emergency services to detect people

Level sensor

Liquid levels Detects levels of petrol in a car tank Detect levels of water in a water tank Detect a drop in water levels due to a leak

Light sensor

Light levels Automatically switching on lights when it gets dark (street lights, headlights)

Magnetic field sensor

Presence and strength Anti-lock braking system Monitoring rotating machinery such as turbines

Moisture sensor

Presence and levels of moisture Monitoring moisture in the soil Monitoring dampness in buildings

pH sensor

Acidity or alkaline Monitoring soil to ensure optimum growing conditions Monitor ph levels in chemical processes

Pressure sensor

Gas, liquid or physical pressure Monitoring tyre pressure Monitoring pressure in pipes during the manufacturing process

Proximity sensor

Distance Monitoring the position of objects in robotics Used in safety systems to prevent objects from colliding

Temperature sensor

Temperature in Celsius, Fahrenheit or Kelvin Used to maintain temperature in swimming pools Used to control temperature in chemical processes

Primary storage

Directly connected to the main processing unit This help increase speed and these type of storage only need small amount as they are quite expensive and high in speed

RAM

Volatile memory (Temporary, need power to operate) Stores data and instructions given by the CPU and devices connected Data will be constantly changed

ROM

Non volatile (data can be retained without power) Stores previous program used by the last boot, bootstrap and BIOS info Contents are fixed and do not change unless certain circumstances

Secondary Storage

That is not directly accessed by the CPU

Secondary storage reasons

Non volatile -> hold data even when computer turns off long-term storage when programs are not currently in use Useful for back-up and archive data as high capacity and slow speed

Magnetic storage (HDD)

Each hardrive contains multiple platters of metal discs coated with a thin layer of magnetic layer Each platter is divide into small sector and track that is wher data is stored Read-write heads read the data using magnets to either change the direction of that magnetic coating or read the coating using resistive force

Solid-state storage

Transistors uses control gates and floating gates Uses NAND or NOR tech

Optical storage

Uses lasers to read pits and lands

Virtual memory

Memory allocated from secondary storage to extend RAM usage and avoid crashing and reduce the need to buy more physical RAM

Page

Fixed length of data block used in virtual memory

Cloud storage

Data storage owned by third party servers over the internet

Public cloud

Client and cloud provider is the same company

Private cloud

Dedicated system with firewall and use by client and storage provider which is associated

Hybrid cloud

A combination of both with the exception of some confidential data stored in private clouds

Cloud storage advantages

Do not have to pay for physical hardware Do not have to be responsible for data security but the provider have to do so Access data anywhere unless loss of network connection The amount of storage is adjustable

Cloud storage disadvantages

Purchase hardware with high cost Need to manage data storage security Do not need online connection May have redundant hardware as storage space cannot freely be adjusts