IAL Information Technology – Unit 1 Notes

1 - Digital Devices

  • Digital devices use computers or microcontrollers.

  • A digital device can receive, store, process, or send digital information.

Hardware

  • Hardware refers to the physical parts of computing devices.

  • Examples include computers, embedded systems, peripheral devices, mobile phones, and storage devices.

Embedded Systems

  • Embedded systems are computer systems performing a specific task, made of hardware and software.

  • Characteristics:

    • Task-specific.

    • Time-constrained.

    • Minimal or no UI.

    • Feedback-oriented.

    • Efficient and cost-effective.

    • Reliable and stable.

  • Examples: consumer electronics, household appliances, medical equipment, automobiles, industrial applications, aerospace, communications.

Mobile Phones

  • Mobile phones use a SIM to connect to a mobile phone network.

  • Smartphones have stronger hardware and extensive mobile operating systems.

  • Specialist phones may have restricted call access or accessibility features for users with disabilities.

  • Tablets are bigger than smartphones with similar features, some using SIM cards for mobile network connectivity.

Home Entertainment Systems

  • Include TVs, video players, audio equipment, and gaming devices.

  • Smart TVs offer internet connectivity and app support.

  • Game consoles allow video game play on TVs, using controllers (including motion sensors).

Home Automation and Smart Assistants

  • Smart homes use internet-connected devices for remote monitoring and management.

  • Virtual assistants like Amazon Alexa provide voice interaction and control smart devices.

Navigation Aids

  • Sat-Nav systems calculate routes using GPS satellites and orientation sensors.

  • Smartphones are replacing specialist in-car navigation aids.

Multifunctional devices and convergence

  • Smartphones are multifunctional devices that converge features from other devices.

  • Examples of convergence include phablets, tablets with mobile network connectivity and cameras with Wi-Fi.

Types of User Interfaces

  • CLI (Command Line Interface): Text-based instructions.

  • Menu-Driven Interface: List of options.

  • GUI (Graphical User Interface): Windows, icons, and menus.

  • Voice Interface: Spoken commands and voice recognition.

  • Gesture Interface: Control via finger movements on touch screens.

Features of digital devices

  • Portability depends on size and weight.

  • Performance relies on processor speed, RAM, storage, bandwidth, and power efficiency.

  • Expansion is possible for PCs via additional components and for smartphones/tablets via expansion slots.

  • Security features protect data via passwords, screen locks, and biometric scanners.

  • Low energy consumption extends battery life.

  • Connectivity enables data sharing.

Security Features

  • Password or PIN entry.

  • Screen locking.

  • Remote data wiping.

  • Biometric scanners.

  • Kensington lock.

Connectivity

  • Short-range protocols: Bluetooth, Wi-Fi, NFC.

Energy consumption

  • Devices use power adapters to convert voltage.

  • "Vampire load" is energy used when adapters are plugged in but not charging.

Technologies used by digital devices

  • GPS, biometrics, touchscreens, sensors, memory, and storage.

Global Positioning System (GPS)

  • GPS provides geolocation and time information using satellites.

  • Needs signals from at least 3 satellites for 2-D position.

  • Does not require internet, but map updates do.

Biometrics

  • Uses physiological characteristics to identify individuals.

  • Examples: fingerprint, retinal, facial, and voice analysis.

Other Technologies

  • Miniaturization, processors, RFID(Radio-Frequency Identification), NFC(Near-Field Communication), QR codes, and connectivity.

Memory & Storage

  • RAM (Random Access Memory) is volatile memory for temporary information.

  • Storage devices (Hard drive, SD card) are non-volatile (permanent).

RFID (Radio-Frequency Identification)

  • Uses radio waves to capture data from tags or labels.

  • Components: RFID tag, reader, and antenna.

  • Tags can be passive (require reader power) or active (have their own power).

  • Applications: inventory, asset tracking, access control, supply chain management.

NFC (Near-Field Communication)

  • Enables wireless data transfer in close proximity (a few centimeters).

  • Modes of operation: peer-to-peer, read/write, and card emulation.

QR (Quick Response) Code

  • 2D barcode for easy information access via smartphone.

  • Can carry much more data than conventional barcodes.

Sensors

  • Proximity, accelerometer, gyroscope, digital compass, barometer and biometric sensors.

Firmware

  • Software programmed on hardware, stored in flash ROM (electrically erasable and reprogrammable).

  • Provides instructions for device communication.

Factors to assess the performance of digital devices.

  • Speed, capacity, portability, bandwidth, and power efficiency.
    *Bandwidth-total transfer rate
    *Power Efficiency- Low-power devices increases battery-life and are better for environment

Binary

  • Digital devices process electronic signals representing one (“on”) or zero (“off”).

  • Bit: a single binary digit.

  • Byte: a group of eight bits.

  • Computers use the base-two numbering system, also known as binary.

Understanding Binary

  • Computers use the base-two numbering system, also known as binary.

  • In this system, each column in the number represents a power of two, with the far-right column representing 2^0 (ones), the next column from the right representing 2^1 (twos), then 2^2 (fours), then 2^3 (eights), etc.

Data Transfer Rate

  • Time = Amount of Data / Data Transfer Rate

  • 1 \text{ MB} = 1024 \text{ KB}, 1 \text{KB} = 1024 \text{ Bytes}, 1 \text{ Byte} = 8 \text{ bits}

What Is “Sample Rate”?

  • Sample rate is how often samples are taken, measured in kHz.

  • 44.1 \text{kHz}: audio CDs

  • 48\text{kHz}: for video

  • dB measures ratios of power or intensity.

Software

  • Software is electronic program instructions or data a computer processor reads.

  • Types: systems software and application software.

Systems software

*Operating systems, file management utilities, anti-virus and disk cleaners.

  • Operating System controls the basic functions of the computer, such as:

    • Device Controlling, Disk Management, Memory Management, Process Management, Maintenance of system security

  • Examples: Microsoft Windows, Mac OS, Linux, Android OS.

System Software Components

  • Operating systems, device drivers, utility software, shells, and windowing systems.

Application software

  • Completes tasks such as creating documents or playing games.

  • Categories: business, graphics/multimedia, personal/education, and communications.

  • Includes word processing, spreadsheet, database, and presentation software.

Software Licensing

  • Copying software is a criminal offense.

Proprietary License

  • Source code is controlled by the creator.
    Examples: Microsoft Office, Adobe Photoshop

Open Source

  • Source code is accessible for modification.

  • Licenses promote collaboration.

Creative Commons (CC) license

*Licenses enables free distribution of copyrighted work

Free software License

  • Licensee has rights to change or redistribute software

Licensing options

*Stand-alone or network licenses, subscription, indefinite license, educational licenses.
*Fixed Term License updates and tech support for a fixed time period
*Indefinite License can be used as long as the H/W and S/W supports it

Software Updates

  • Updates provide fixes and enhancements.

Software Upgrade

*replaces old software with an improved version

  • Updates fix bugs and improve functionality; frequent and often free.
    *Compatibility- the capacity for 2 systems to work together without having to be altered to do so.

2 – Networks

  • A computer network connects computers to share resources.

Networking models

  • Client-server and peer-to-peer (P2P).

Client-server

  • Clients request information, servers provide it.
    *Server manages the info

Peer-to-peer (P2P)

*All clients are servers

  • Each computer stores files and acts as a server.

Ad hoc Networks

  • Devices communicate directly without a central access point.
    *Examples: Mobile Ad hoc networks, Vehicular ad hoc networks

Tethering

  • Connecting a mobile phone to another device to share its internet connection.

Features and purposes of network communication protocols

  • Wireless (Wi-Fi, ZigBee, Bluetooth), cellular (GSM), infrared and Ethernet.

Wireless - Wi-Fi

  • Uses radio waves for high-speed connections.

ZigBee

  • Low-power, low data-rate, and close proximity.
    *Devices: Amazon Echo Plus, Bosch Security Systems

Bluetooth

  • Short-range wireless communication.
    *Device Class: 3, 2, 1

Cellular – Global System for Mobile (GSM) communications (3G/4G)

  • GSM is a digital cellular communication technique that uses Time DiVision Multiple Access.
    *Mobile Phone Generations 1G-4G LTE

Infrared

  • Short-range communication among computer peripherals.

Ethernet

  • Wired LAN technology for device communication.
    *It is typically less vulnerable to disruptions and offers a degree of network security

Transmission Control Protocol/Internet Protocol (TCP/IP)

  • TCP divides messages into packets, IP addresses packets to the right destination.
    *TCP/IP functionality is divided into four layers

Voice over Internet Protocol (VOIP)

VOIP lets you have voice and multimedia content and is cheap and reliable. Ways to work a VOIP
*ATA, IP Phones, Computer-to-computer

Session Initiation Protocol (SIP)

  • The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating real-time sessions that include voice, video and messaging applications.
    *TEXT-based protocol

7-layer open systems interconnection (OSI) Model.

  • Conceptual framework describing networking functions using layers.
    OSI Model 7 Layers
    *Application, Presentation, Session, Transport, Network, Data Link, Physical

  • A layer can be removed/edited and replaced without affecting any of the other layers

Network design and implementation

  • A transmission medium is a physical path between the transmitter and the receiver

  • Wireless Communication technology
    *Types of Wireless : Satellite Communication, Infrared Communication, Broadcast Radio, Microwave Communication, WiFi

Advantages of Wireless Communication:

  • Data transfer faster and high speed, Less maintenance, The internet can be accessed from anywhere

Disadvantages of Wireless Communication:

  • Easily capture signals, Secure protection for the network so the information will not be misused

Wired Transmission and Features:

  • It is also referred to as Guided or Bounded transmission media

  • High Speed, Secure, Used for comparatively shorter distances
    *Twister Pair Cable, Coaxial Cable, Optical Fibre Cable, Power Line

Twisted Pair Cable:

*Unshielded Twisted Pair (UTP)
*Shielded Twisted Pair (STP)

Coaxial Cable:

*It has an outer plastic covering containing 2 parallel conductors each having a separate insulated protection cover
Cable TVs and analog television networks widely use Coaxial cables

Optical Fibre Cable:

*Uses concept of light reflections

Power Line Communication (PLC)

Carries data on a conductor that is also used simultaneously for AC electric power transmission

Understand a variety of network metrics:

  • Speed, Bandwidth,

  • Throughput-actual amount of data succesfully sent

  • Scalability-potential to be enlarged to accommodate growth

  • Latency-how long it takes for data to travel.
    *Packet Loss occurs when one or more packets of data travelling across a computer network fail to reach their destination
    *Jitter is any deviation in, or displacement of, the signal pulses in a high-frequency digital signal

Network Components

  • Hub, Switch, Bridge, Gateway, Router, Modem, Repeater,
    *Server, Network Interface Card (NIC), Wireless access point

Gateways

  • Gateways slow the flow of data and can therefore potentially become bottlenecks

Routers

*ADSL Routers that are used in homes and small offices combine the features of a switch, WAP and a router

  • Repeater :Used to boost signals so that it can go further(Edexcel)

Understand the characteristics and function of IP addressing

  • Numerical label assigned to each device connected to a computer network using IP.
    Provides network identification and location and IP Addressing

IP Addressing

  • Static and Dynamic IPs.

  • Benefits of dynamic IP addresses. 1)doesn't cost you anything extra
    *2)It's carefree, automatic and reliable with very little work on your end.

DHCP: The Networking Protocol That the Gives You an IP Address

*DHCP assigns you (and everyone) their IP address.
DHCP is a part of the application layer of the TCP/IP protocols.

MAC (Media Access Control) Address

*A MAC address is a unique number that is programmed into every NIC
MAC addresses are expressed in hexadecimal

URL Uniform Resource Locator

*Is used to specify addresses to the World Wide Web.

DNS (Domain Name System (or Service or Server))

*Translates URL the correspoding IP by looking url in its Table; if url is not there it sends it to Higher DNS

Network security

  • The organization's strategy for ensuring the security of its assets and all network traffic.

Methods used to secure a network using both hardware and software

  • Firewall, security settingsanti-malware, user controls/access/rights/profile, authentication types, encryption techniques, physical controls
    *Security settings things users should use to secury their wireless network
    1)Open your router settings page (a unique password on your router 2)Change your Network's SSID name.

3 – The Online Environment

The internet and the World Wide Web

  • The Internet is a global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide.

  • The World Wide Web (WWW), information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the Internet
    Negative impacts of World Wide Web sites created with the intention of providing suicidal persons with information on how to go about killing themselves

Static and dynamic web pages

  • Static Web pages contain the same prebuilt content each time the page is loaded, while the content of dynamic Web pages can be generated on-the-fly.

  • Client -Side Environment is Usually Scripting on the Browsers while Server-Side HTML s are the Web Servers

Operating Online

*Online communities used to socialize, share information, play games, work, learn, and create
*

Security risks to personal data stored online and methods of protection

*Following are some guidelines to increase the safety of your devices and data online;
securing devices, install antivirus software, use strong passwords , and back up data.

Digital Footprint

*Digital Foot Print is a trail data you create will is using the internet some examples or Websites visited and social data used to build the online reputation and displayed on the internet.

Monetization opportunities provided by online communities:

  • use of customer data with targeted advertising,
    pay-per-click advertising, Selling of customer data, paid subscriptions(paywalls) and sponsered content.

Cloud Storage

*Online space used to store data which involves stashing data on hardware in a remote physical location accessing can be Done easily in device through the device of your own device, files can be sent to the data server maintained by cloud
Advantages of cloud storage Bandwitdth,Accessability,Desaster Recovery.
Issues that could raise in cloud storage
Usability
Bandwidth
Accessibility
Data Security
Software

Cloud computing

*Cloud computing is the on-demand availability of computer system resources without direct active management by the user.
*Infrastructure as a Service (IaaS) – where big players like Amazon and Google rent out immense computing infrastructure to other companies;
*Platform as a Service (PaaS) – online spaces where developers create online applications for specific sets of users;

  • One of the things that make it so powerful is the fact that that thousands,
    even millions, of people can interact with the same bit of information simultaneously*Software as a Service (SaaS) – where clients use software over the internet. Developers can use Microsoft Azure as a platform for building and deploying application, Facebook and gmail are just simply an example.

4 – IT Systems

  • Is a number of components working towards a common goal
    IT constits HW/ SW/ PEOPLE/ PROCESSES
    Data Flow Diagrams (DFD)
    SYSTEM flows charts
    Evaluation: a process of determining if the solution you are aiming for is met with satisfaction
    Fitness for purpose-Software is meet if it is with requirement determine
    If software is not fit for purpose then necessary visits previously

5 - Data and Information

Data V Information
*Data =Words of data without context
*information= a collection of words that has context
Structures such as senteneces are needed to give the meaning of the information.

Linked database

The way to avoid insert, delete and update anomalies is to design relational databases that use two or more linked tables to store data.

Primary and foreign keys

(Main important Keys)
PRIMARY key field used uniquely to identify every record
FOREIGN key primaray key from another table that appear

Structures and links

A database to store information in organized databases use from people such as Facebook etc The main file, records and fields. Every data will be stored in the different field.

ER diagram

ENTITY RELATIONSHIP diagram illustrates relationship, people between different data with one to one relations,one to many , many to amy data relationship

ER Diagram examples

Data,Customer

Issues with Many-to-many

Relationships cannot is difficult to track