© 2023 Eva Trope. All Rights Reserved
IT THEORY
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,© 2023 Eva Trope. All Rights Reserved
SYSTEM TECHNOLOGIES 3
INTERNET AND COMMUNICATION TECHNOLOGIES 21
SOCIAL AND ETHICAL ISSUES 42
DATA AND INFORMATION MANAGEMENT AND SOLUTION DEVELOPMENT 46
Copyright © Eva Trope 2023. All rights reserved. This material is protected by copyright law and is
intended for the personal use of the purchaser. Reproduction, distribution, or sharing of this content, in
whole or in part, without the express written permission of the copyright owner is strictly prohibited.
Unauthorized use may result in legal action.
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SYSTEM TECHNOLOGIES
Compression Reduction of a file’s size for storage optimisation or quick transfer
Decompression Extraction of a compressed file to return it to its original form
Archiving Storing of a file in a separate compressed archive to save space
Backup Copying data to a secure location in case of data loss
Registry OS’s function to record installations’ changes to the system
Hardware Physical components of the computer system
Software Non-physical components of the computer system
Data Unorganized facts
Information Processed data with context
Processing Power A combination of speed, number of cores and number of instructions processed per
second
Operating System A collection of programmes that manage hardware and allow software to run, stored
in RAM
Kernel The smallest part of the Operating System in RAM
Bus Transporter of data (4 or 8 bytes)
RFID Data transference via radio signal attached to an object
Modular Design Division of parts of a computer into modules connected via motherboard for
customisation according to needs
Application Software that carries out tasks
Stand-Alone/ An application that does not interact with other software (besides the OS) e.g.
Desktop Microsoft Word
Application
Network An application that runs on nodes of a client-server network
Application
Synchronization The process where data on different devices are consistent with the latest version via
communication software
Motherboard PCB that links electric peripherals such as the CPU and RAM, connected by busses
Onboard Unremovable but disableable hardware component embedded into the circuit e.g.
controller sound card, network card, GPU, WLAN
RAM Temporary memory that stores open programmes, measured in size, type and speed
CPU Chip on the motherboard that interprets and executes instructions, measured by
clock speed, number of cores, and cache
Co-processor Processes parallel to CPU to decrease its burden
Cache memory SRAM chips that store pre-fetched instructions from RAM incase they are needed
BIOS Non-volatile firmware that initializes hardware when the device starts
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Firmware Software on a hardware device, usually ROM. Permanent unless updated.
ROM Non-volatile memory that stores data
Peripheral Input, Output and Secondary Storage devices connected to the Motherboard
Component Anything placed directly on the Motherboard
Secondary Non-volatile storage for later retrieval
Storage
Removable Media Removable Secondary Storage
Media Stores data
Hard drive Device that stores programs and data inside the computer case
Read/Write Head Scanner on a disk for magnetic data
Hybrid Drive A drive containing an HDD joined with a flash memory using SSD technology
Flash Drive A small, fast, expensive SSD that connects via a USB port
Optical Drive A non-volatile outdated disk with data burned on using a laser. Low storage capacity
but cheap.
SD Card Small Flash memory card with high memory
Optical Mouse Reliable mouse that uses LED and has no mechanical parts
Scanner Input device that analyzes an image and converts it to a file
OCR Scanner software that converts an image with text to Unicode
dpi Measurement of Scanner resolution
Barcode Scanner Scanner that stores information about a product, then reads the pattern of reflected
light of a barcode from a red LED light
Barcode A pattern of black lines that is decoded by the scanner to represent data
QR Code Two dimensional set of squares on a white background
Magnetic Stripe Scanner that decodes information on a magnetic strip
Reader
Biometric Device Scanner that recognises humans based off of physical characteristics
Microphone Input device that converts sound energy into digital energy using a diaphragm
Sensor A device that converts real-world property measured in physical parameters into data
consisting of electronic signals
Accelerometer Sensor that gauges the tilt of a smartphone to determine the orientation that the
screen should show
Resolution The number of pixels on a monitor, across and downwards
Impact printer Printer with a hammer that touches a ribbon on paper
Non-impact Printer that only has the ink or toner touching the paper
Printer
Speaker Output device that receives audio input from a sound card and produces sound
waves
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Internal Amplifier Device inside a speaker that amplifies sound
Headphones Output device that converts digital data into sound waves with a diaphragm
Headset A combination of a microphone and headphones
Port Interface between a computer and peripheral devices
USB Interface that enables communication between devices and a host
Thunderbolt Apple Interface using USB-C port
HDMI Digital interface with tapered edges that transmits and receives audio and video
signals
Driver Software that allows software to send instructions to hardware and provides software
information about hardware as an interface between the device and OS
Programming tool A programme that creates or supports other programs and interacts with device
resources
WORA Concept of writing code on one platform that can run in multiple
Source Code Original code that the programmer writes,
Object code Executable code
Disk Software that rearranges fragmented data on a mechanical hard disk so data writes
Defragmenter and loads faster
Software License Legal description of how software can be used and copied
License Manager Enforcer of license terms that protects the software vendor from piracy
Piracy Illegal copying of software
Proprietary A license that doesn’t allow distribution or copying and doesn’t provide source code
License with a EULA agreement
Free and Open License that shares source code
Source License/
Copyleft License
GNL License that allows modification and distribution of software with credit
Creative License that gives the creator copyright but allows copying and distribution with credit
Commons
License
Freeware Free software without source code that can be used but not redistributed
Freemium Software with limited free functions and extra paid ones, usually unlocked by buying
Software a license key.
Subscription Monthly or annual payments to access service/software
License
Pay-As-You-Go Payments only for processes/storage used
License
Pay-By-Instance Payments per use for once-off services or to test the app
License
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Educational Products free to accounts part of a school domain e.g. G Suite, Office 365
Licensing
Domain Group of accounts in an organization with users, apps, security and permissions
managed by administrator
Malware Malicious software that harms a computer
Virus Program that damages the system and can modify itself to avoid detection. Spread
via removable media, attaching itself to emails or downloading from the Internet and
infecting the file it’s downloaded to, must be clicked on to operate
Spyware Software installed without permission to intercept or take partial control over user’s
interaction with the computer
Keystroke-logging Program that records keystrokes of infected users and then transmits this data via
the Internet to a criminal so that they can access the user’s passwords
Adware Unwanted but usually harmless software that automatically displays or downloads to
a computer and can slow it down. Accesses cookies and personal data stored in the
Internet to customize adverts.
Signature Identifying piece of code embedded into a virus
Anti-Malware Programs that guard against malicious threats e.g. by permitting access to the
computer
Anti-Virus Programs that find the signature of a virus and take appropriate action
Bandwidth Theoretical amount of data that a communication channel can transfer per unit time
(Kbps/Mbps/Gbps)
Throughput Actual speed of data
Register size Measured in bits (32/64), indicated how much data is processed at a time
Accumulator Register that stores the result of ALU executions
SRAM Fast and expensive RAM without capacitors (no refreshing needed)
Capacitor Electricity storage in RAM that is constantly refreshed, increasing access time
Serial Processing Single core CPU sequential processing of instructions
Parallel Distributed simultaneous processing of instruction parts on microprocessors
Processing
Multiprocessing Multiple cores parallel processing
Hyperthreading Preloading of next thread into a second set of logical cores to reduce time of
process, giving the appearance of parallel processing
Thread Part of a program consisting of a set of instructions
Process Entire program consisting of threads in CPU
Context switching Switching of CPU between registers
Control bus Wire from CU to RAM that enables RAM to read/write data when needed
Address Bus Unidirectional wire from Memory Address Register in CPU to RAM that requests data
and contains where to find it
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Data Bus Wire from RAM to Memory Data Register in CPU that sends requested data
Bus size Number of bits data bus can deliver, width dictates register size
External Bus Electric circuit that connects external devices e.g. storage, mouse, keyboard etc via
ports
DRAM RAM with capacitors, refreshed multiple times per second
SDRAM DRAM refreshed in sync with CPU
DDR SDRAM SDRAM that transfers data twice every clock pulse
Latency Time taken for a component to respond
System Clock Microchip that regulates timing of computer functions to synchronize events
Clock Speeding up a component/ system by changing the multiplication factor of the
multiplication/ System Clock to increase clock rate
Overclocking
FSB Old parallel bus that connected components on motherboard, replaced by
point-to-point serial connections. Consisted of Data, Address and Control busses
PCI Express Fast external bus interface that connects graphics cards, RAID cards, WiFi cards and
SSDs
SATA Computer bus interface that connects mass secondary storage devices to the
motherboard
NVMe Computer communication bus interface that connects SSDs to the motherboard
M.2 Format Small, high speed format for interface
Boot sequence The checking of hardware and loading of OS onto RAM by the boot loader when the
computer is switched on
MBR Section of code on HDD that loads and operates the kernel
CMOS Volatile memory chip for hardware settings and user settings, powered by battery
Hardware settings Types of hardware installed
UEFI New initializing software to replace BIOS that doesn't go through the MBR
Interrupt Signal sent that a process needs immediate processing
IRQ Unique device number to identify which device is causing an interrupt
Buffer Temporary storage in RAM that improves throughput
IO Range Buffer for a specific input or output
Multitasking An OS technique that gives the appearance of running programs simultaneously by
context switching
Multithreading Multiple threads running simultaneously on separate CPUs
Virtual memory A portion of secondary storage containing excess data when RAM is full, can slow
down performance if slower secondary storage (e.g. hard drive)
Swapping Copying the entire process address space to virtual memory
Paging file Part of data stored in Virtual Memory
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Translator Software programming tool that converts source code into code for CPU to
understand
Compiler Translator that translates and executes all code at once. A one-stage compiler
directly converts source code into machine code, while a two-stage compiler breaks
the process into two steps: converting source code into an intermediate
representation and then translating that representation into machine code.
Interpreter Translator that translates and executes source code line-by-line
High-Level Programming language resembling human language (Python, JavaScript, Delphi,
Language Java)
Low-Level Language closer to machine language (machine language, assembly language, C)
(Assembly)
Language
Assembler Program that converts low-level language code to machine language
Machine Code Compilation of source code through a machine-dependant file (object code)
Generation
Bytecode Compiled object code from source code that an interpreter on any device converts
into machine code without needing a compiler
Intermediate Internal representation of code in a two-stage compiler
Representation
Machine Cycle Fetching of an instruction from memory, decoding in CU to a low-level language,
executing in ALU and storing the instruction in memory/ sending to output
Product Key/ Unique code that ensures software is purchased legally and the product is licensed
Activation Key/ to you, and activated it if it is
Activation Code
Uninstallation Utility that removes all parts of a program from the system and updates the registry
Hot-Swappable Can be installed without restarting the computer
Scheduling Utility that runs programs automatically under specified conditions
THE COMPUTER
Advantages:
● Fast
● Online shopping, banking, mail
● Less paper
● Less travel
● Efficient software updating
Disadvantages:
● Electrical failures
● Hacking
● Scams and fraud
● Injuries
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● Non-biodegradable
● Used a lot of electricity
● Hardware and software outdated quickly
Input
● Keyboard
■ High potential for errors, best to avoid
● GUI Components
○ Menus, check boxes, drop down menus etc
■ To prevent user errors
● Pointing device
○ Mouse
● RFID tag
○ Pet trackers
○ Clothing tags to prevent theft
● Scanner
○ Barcode Scanner
○ QR Scanner
■ QR contains more information than barcode
■ No hardware needed, only camera
○ Magnetic Stripe Reader
○ OCR
○ Biometric Device
■ Fingerprints
■ Retinal Scans
■ Voiceprints
● Microphone
● Sensor
○ Accelerometer
○ Autopilot System
○ GPS sensors
■ LBS
● Proximity-based marketing
● Real-time travel info
● Roadside assistance by tracking location
● Mobile workforce management by tracking employee’s location
● Fraud prevention by comparing transaction’s location to client’s phone’s
location
● Geotags on social media to market and share events
Output
● Speaker
● Headphones
● Monitor
○ Screen size measured diagonally
○ LCD screens are most common
● Printer
○ 3D Printer
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■ Builds an object in slices
○ Laser printer
○ Inkjet printer
LASER INKJET
Prints high volumes Prints low volumes
Low quality High quality
Expensive machine Cheaper machine
Cheap toner Expensive ink
Image burned on quickly Image printed slowly
Non-impact
Communication
● Instant messaging (email, Whatsapp etc)
● Via wireless router, hotspot, ADSL router, SIM card
Desktop
● modular design (space for added components)
● cabled - reliable
● good memory
● fast
● good graphics
● 3-4 PP
Laptop
● mobile, compact
● limited graphics due to smaller screen
● 3-4 PP
Tablet
● touch screen/ stylus
● 1-2 PP
Smartphone
● Apps, computing, connectivity
● 1-2 PP
Smart wear/ wearable technology
● Simpler than smartphone
● Information (vitals, statistics) exchanged through Internet without human intervention
● Can contact emergency services if needed
● Pairing with smartphone
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