Aim A: Devices & Peripherals | Software & System Choice
Aim B: Connectivity & Networks
Aim C: Online Systems & Communities
Aim D: Threats to Data & Protection
Aim E: Legal & Regulatory Framework
Aim F: Planning & Communication
Learning Aim A
Devices & Peripherals | Software & System Choice
Input Devices
Keyboard: Text input, accurate typing, requires flat surface
Mouse: Pointer control, GUI navigation, intuitive use
Touchpad: Laptops, pressure-sensitive, alternative to mouse
Scanner: Converts paper to digital, OCR capability
Touchscreen: Direct interaction, intuitive, responsive
Microphone: Audio input, speech recognition, video calls
Output Devices
Monitor (LCD/OLED): Visual display, resolution matters, refresh rate for gaming
Printer (Inkjet): Color printing, slower, cost-effective, used for photos/graphics
Printer (Laser): Fast printing, monochrome, higher cost per unit, great for documents
Speakers/Headphones: Audio output, surround sound options, wireless available
Projector: Large display, presentations, brightness (lumens) important
Storage Devices
HDD vs SSD Comparison Table
Feature
HDD
SSD
Technology
Magnetic spinning disk
Flash memory chips
Speed
Slower (200-300 MB/s)
Faster (500-3000 MB/s)
Cost
Cheaper
More expensive
Reliability
Moving parts fail
No moving parts
Capacity
Higher (4TB+)
Growing (2TB common)
Best for
Storage, archives
OS, programs, gaming
Scenario: A video production company needs to store 10TB of raw footage. They should use HDDs for cost-effectiveness. But they also want the editing software on fast storage for quick response times, so they add an SSD for the operating system and applications.
Other Storage
USB Flash Drive: Portable, universal compatibility, 32GB–1TB typical, easy to lose
Optical Media: CD (700MB), DVD (4.7GB), Blu-ray (25GB+), can degrade over time
Temporary Memory
RAM vs Cache Comparison
Aspect
RAM
Cache
Speed
Nanoseconds
Sub-nanoseconds
Size
GigaBytes (8-32GB)
MegaBytes (8-20MB)
Cost
Moderate
Very expensive per byte
Volatile
Yes
Yes
Location
Separate chip
On CPU chip
Scenario: A graphics designer opens Photoshop with a 500MB image. The OS loads in RAM (2GB used). The CPU uses cache to temporarily store pixel data it's processing. With more RAM, the system won't need to swap to disk, keeping everything fast.
A1.3 Drawing Skills: Flowcharts & System Diagrams
How to draw a flowchart
Identify the process order from the scenario.
Use Start/End terminal shapes and connect everything with arrows.
Use process boxes for actions and diamonds for yes/no decisions.
Use arrows to show data direction and label key links where needed.
Keep layout tidy and match the scenario context.
Learning Aim B
Connectivity & Networks
Wired vs Wireless Connection Comparison
Feature
Wired
Wireless
Speed
Very fast (1-10 Gbps)
Good (50-600 Mbps)
Reliability
Stable, no interference
Can have interference
Mobility
Limited by cable
Very mobile
Cost
Installation costs
Low cost once set up
Best for
Fixed servers, high data
Laptops, mobile devices
Scenario: A school office needs desktop computers wired with Ethernet for maximum speed and stability. But in classrooms, teachers use laptops and need Wi-Fi to move around. The school uses both technologies for different purposes.
Network Topologies
Network Topology Comparison
Topology
Structure
Reliability
Cost
Star
Devices → Central hub
Good (hub failure=down)
Moderate
Ring
Devices in circle
Fair (break affects all)
Moderate
Bus
Linear chain
Poor (cable break=down)
Low
Mesh
Multiple connections
Excellent (multiple paths)
High
Scenario: A hospital needs reliable patient data networks. Using star topology is standard and cost-effective. But critical ICU units use mesh topology so if one connection fails, vital signs still transmit through alternative paths.
Network Types & Protocols
PAN: Personal devices, Bluetooth, 10m range
LAN: Same building, fast, secure, office/school
WAN: Multiple locations, cities/countries, via Internet
VPN: Encrypted tunnel, remote access, public network protection
Key Internet Protocols
SMTP: Sends email
POP/IMAP: Retrieves email (IMAP for multiple devices)
HTTP/HTTPS: Web traffic (HTTPS for secure, port 443)
FTP/SFTP: File transfer (SFTP encrypted)
DNS: Converts domain names to IP addresses
TCP/IP: Foundation of internet communication
Bandwidth & Latency
Bandwidth: Amount of data per second (Mbps/Gbps), higher = faster
Latency: Delay in transmission (milliseconds), lower = more responsive
Both matter: High bandwidth but high latency = fast but delayed
Learning Aim C
Online Systems & Communities
Cloud Service Models
SaaS vs PaaS vs IaaS Comparison
Model
What's Provided
Examples
Best For
SaaS
Complete applications
Google Workspace, Teams, Slack
End users, everyday work
PaaS
Development platform
Heroku, App Engine
Developers building apps
IaaS
Computing infrastructure
AWS, Azure, Google Cloud
Organizations, full control
Scenario: A startup needs email/collaboration (SaaS: Google Workspace), development tools (PaaS: Heroku), and flexible servers (IaaS: AWS). They use all three layers, scaling and paying only for what they use.
Cloud Deployment Models
Cloud Deployment Model Comparison
Model
Access
Cost
Security
Best For
Public
General public
Low
Standard
Startups, cost-conscious
Private
Single organization
High
High
Finance, healthcare, sensitive
Hybrid
Mix of both
Moderate
Good
Flexible organizations
Scenario: A bank uses private cloud for secure customer financial data (high security). But for non-sensitive apps like email (SaaS), it uses public cloud to save costs. A hybrid approach balances security and budget.
Cloud Benefits & Challenges
Benefits: Low cost, scalability, automatic updates, global access, high availability
Challenges: Internet dependency, provider outages, data lock-in, latency, data sovereignty concerns
Remote Working Tools
VPN: Encrypted tunnel to company network
Remote Desktop: Control office computer from home
Cloud Storage: Files accessible from anywhere (OneDrive, Google Drive, Dropbox)
Collaboration: Video conferencing, instant messaging, real-time editing
Learning Aim D
Threats to Data & Protection
Data Threats Overview
Data Threat Comparison
Threat Type
Source
Detection
Prevention
External (Malware)
Outside network
Easier (obvious)
Antivirus, firewalls
External (Hacking)
Remote attackers
Hard (logs needed)
Strong passwords, MFA
Internal (Intentional)
Employees
Hardest (trusted)
Access controls, monitoring
Internal (Accidental)
Employee error
Moderate
Training, enforcement
Scenario: A healthcare employee accidentally emails patient records to the wrong address (accidental internal threat). The hospital must notify the patient (legal requirement), fix processes, and provide credit monitoring. This costs more than preventing malware with antivirus software alone.
External Threats
Viruses: Self-replicating code, needs host program
Worms: Self-replicating, spreads over network
Trojans: Disguises as legitimate software, opens backdoors
Ransomware: Encrypts files, demands payment
Spyware: Monitors user activity, steals data
Hacking: Brute force, phishing, SQL injection, social engineering
DDoS: Overwhelms servers with traffic, causes outage
Scenario: A bank needs to send loan documents to a customer over email. It uses asymmetric encryption (public key) to encrypt the document. Only the customer's private key decrypts it. Even if someone intercepts the email, they can't read it without the private key.
Security Software
Antivirus: Detects and removes malware, real-time scanning, updates signatures
Firewalls: Hardware and software, monitors incoming/outgoing traffic, rule-based control
HTTPS/SSL/TLS: Encrypts web traffic, port 443, Certificate Authority validation
VPN: Encrypted tunnel to company network, masks IP address
Digital Certificates: Proves website authenticity and identity
Backup & Recovery
Backup Types: Full (all data), Incremental (changes only), Differential (changes since last full)
Storage: Local (on-site), Cloud, Off-site (different location)
3-2-1 Rule: 3 copies, 2 different media types, 1 copy off-site
RTO/RPO: Recovery Time Objective, Recovery Point Objective
Testing: Regular disaster recovery drills to ensure it works
ICO: Information Commissioner's Office (data protection)
Ofcom: Office of Communications (telecommunications)
ASA: Advertising Standards Authority
IPO: Intellectual Property Office
Learning Aim F
Planning & Communication
Project Planning
Planning Fundamentals
Scope: What needs to be delivered?
Goals: Clear, measurable targets
Deliverables: Specific outputs to be produced
Resources: People, equipment, budget needed
Timeline: Start date, end date, milestones
Project Management Methodologies
Waterfall vs Agile Comparison
Feature
Waterfall
Agile
Approach
Sequential, linear phases
Iterative, sprints (1-4 weeks)
Planning
Detailed upfront
Continuous planning
Testing
At the end
Throughout (continuous)
Changes
Expensive, difficult
Easy, expected
Delivery
All at once
Incremental releases
Best for
Fixed requirements
Changing requirements
Scenario - Waterfall: Building a bridge requires extensive planning upfront—changes during construction are very expensive. All requirements must be perfect before starting.
Scenario - Agile: Building a mobile app with uncertain market needs. Start with core features (1-week sprint), get user feedback, adjust in next sprint. Flexibility helps discover what users actually want.