Know and understand the characteristics, uses and issues relating to cloud computing

Cambridge IGCSE ICT 0417 – Topic 4: Networks and the Effects of Using Them

Objective

Know and understand the characteristics, uses and issues relating to cloud computing.

1. What is Cloud Computing?

Cloud computing is a network‑based model that delivers on‑demand access to shared resources – such as servers, storage, applications and services – over the Internet. Users can employ these resources without owning or managing the underlying hardware.

2. Key Characteristics of Cloud Computing (all five)

CharacteristicExplanationContrast with Traditional (on‑premises) ComputingClassroom / Real‑world Example
On‑Demand Self‑ServiceUsers can provision computing resources automatically, without contacting the provider.In a local server room a technician must manually install OS, configure storage, etc.Students click a button in the school’s Azure portal to spin up a virtual machine for a programming lab.
Broad Network AccessServices are reachable over the network via standard devices (PCs, tablets, smartphones) and standard protocols (HTTP, HTTPS, APIs).Traditional services often require a specific client or a LAN connection.Teachers edit a shared Google Slides presentation from any classroom computer or home laptop.
Resource PoolingPhysical resources are pooled to serve many consumers using a multi‑tenant model; each consumer’s data is isolated.On‑premises each department may need its own dedicated server.Several schools share the same physical storage array in a public cloud, yet each school’s files remain separate.
Rapid ElasticityResources can be scaled up or down quickly, often automatically, to match demand.Adding capacity to a local data centre can take weeks of procurement and installation.During exam week a school expands its virtual lab from 20 to 200 VMs, then reduces it afterwards.
Measured ServiceResource usage is monitored, controlled and reported, giving transparency for both provider and consumer.Traditional environments rely on manual meter‑reading or estimates.The school receives a monthly usage report showing CPU hours, storage GB and network traffic, enabling cost control.

3. Typical Uses of Cloud Computing (syllabus list)

  • File‑sharing and collaborative document editing (e.g., Google Workspace, Microsoft 365).

  • Online testing and assessment platforms (e.g., Moodle Cloud, ExamSoft).

  • Backup, archiving and disaster‑recovery for school data.

  • Virtual labs for programming, graphics or networking courses.

  • Streaming of educational video content (e.g., YouTube, Vimeo).

  • Hosting school websites and intranets.

  • Document‑production & spreadsheet analysis – using Google Docs or Sheets for group reports and data analysis, directly linking to later practical papers.

4. Cloud Deployment Models

ModelDefinitionTypical UsersProsCons
Public CloudServices offered over the public Internet and available to any organisation or individual.Small businesses, individuals, large enterprises, schools using SaaS.Low cost, high scalability, no capital investment.Less control over data location; higher perceived security risk.
Private CloudCloud infrastructure operated solely for a single organisation, either on‑premises or hosted.Government agencies, large enterprises, schools with strict data‑protection policies.Greater control, enhanced security and compliance.Higher cost, requires internal expertise.
Hybrid CloudCombination of public and private clouds linked by technology that allows data and applications to move between them.Businesses or schools needing flexibility – e.g., keep sensitive data private while using public cloud for less‑critical services.Best of both worlds – cost‑effective and secure.Complex management, integration challenges.
Community CloudInfrastructure shared by several organisations with common concerns (e.g., security, compliance, jurisdiction).Research consortia, groups of schools within the same district, industry alliances.Shared costs, common governance, easier compliance with sector‑specific regulations.Limited to members; requires strict agreements on data handling.

5. Cloud Service Models

ModelWhat is ProvidedTypical Example ServicesSchool‑Based Example
Infrastructure as a Service (IaaS)Virtualised computing resources – servers, storage, networking – delivered over the Internet.Amazon EC2, Microsoft Azure Virtual Machines, Google Compute Engine.School creates a virtual lab of Windows Server VMs on Azure for ICT lessons.
Platform as a Service (PaaS)Platform that lets customers develop, run and manage applications without dealing with the underlying hardware.Google App Engine, Heroku, Microsoft Azure App Service.Students develop a web‑app for a geography project using Google App Engine.
Software as a Service (SaaS)Fully functional software delivered over the Internet on a subscription basis.Google Workspace for Education, Microsoft 365, Dropbox.Teachers use Google Classroom to distribute assignments and give feedback.

Note for teachers: PaaS is rarely examined in the IGCSE practical papers, but understanding it helps students answer AO3 evaluation questions that compare different cloud solutions.

Distinguishing Service vs. Deployment Models

AspectService Model (IaaS/PaaS/SaaS)Deployment Model (Public/Private/Hybrid/Community)
What it describesLevel of management the provider offers (infrastructure, platform, or software).Where the cloud resources are hosted and who can use them.
Decision focusChoose based on the amount of control you need over the environment.Choose based on security, compliance and cost considerations.

6. Benefits of Cloud Computing (must cover five)

  • Cost Efficiency – Pay‑as‑you‑go pricing reduces capital expenditure; schools only pay for what they use.

    AO2 link: calculate monthly cost from provider price tables.

  • Scalability – Resources can be increased or decreased quickly to match demand (e.g., expanding a virtual lab for a project).

    AO2 link: evaluate why rapid elasticity is useful for exam‑time spikes.

  • Accessibility – Data and applications are reachable from any Internet‑connected device, supporting remote learning.

    AO2 link: discuss how broad network access enables home study.

  • Reliability – Redundant data centres improve uptime; many providers guarantee >99.9 % availability.

    AO2 link: compare reliability of cloud vs. a single on‑site server.

  • Focus on Core Business – IT staff can concentrate on teaching support rather than hardware maintenance.

    AO2 link: explain how measured service frees staff for other tasks.

7. Issues, Risks and Mitigation Strategies (syllabus requirement)

  1. Security – Data may be exposed if not properly protected.

    Mitigation: encryption at rest and in transit, strong Identity & Access Management (IAM) policies, multi‑factor authentication (MFA), regular security audits.

  2. Privacy – Must comply with data‑protection legislation (e.g., GDPR, UK Data Protection Act).

    Mitigation: choose providers with relevant certifications, store data in compliant jurisdictions, conduct Data Protection Impact Assessments.

  3. Vendor Lock‑In – Difficulty moving services or data to another provider.

    Mitigation: use open standards, maintain local backups, negotiate clear exit clauses in contracts.

  4. Downtime / Service Availability – Reliance on provider’s uptime guarantees.

    Mitigation: review Service Level Agreements (SLAs), implement multi‑region redundancy, have a fallback plan (e.g., local backup servers).

  5. Data Transfer Costs – Charges for moving data in/out of the cloud can be high.

    Mitigation: consolidate data transfers, use caching/CDNs, monitor bandwidth usage.

Exam‑style Question Stems (AO2/AO3)

  • “Explain two ways in which a school can reduce the security risks associated with storing student records in a public cloud.”

  • “Compare the benefits of using a SaaS learning‑management system with those of running the same system on an on‑premises server.”

  • “A school is considering moving its backup files to a community cloud shared with other schools in the district. Identify two advantages and two disadvantages of this approach.”

  • “Calculate the monthly cost for a cloud‑based virtual lab that uses 8 VMs at \$0.09 per hour each and 750 GB of storage at \$0.018 per GB per month.”

8. Case Study – Protecting Student Records in the Cloud

A secondary school adopts a SaaS learning‑management system (LMS) that stores grades and personal information. To meet GDPR requirements the school implements the following measures:

  • All data is encrypted with AES‑256 before transmission (HTTPS/TLS) and stored encrypted at rest.

  • Role‑based access is enforced through the provider’s IAM system – only ICT staff and class teachers have appropriate rights.

  • Multi‑factor authentication is mandatory for all staff logins.

  • The provider supplies ISO 27001 and SOC 2 compliance reports, which the school reviews annually.

  • A quarterly data‑export is performed and stored on an on‑premises NAS for disaster‑recovery.

9. Calculating Cloud Costs

Example 1 – Simple IaaS Scenario

Assume a school runs 10 virtual machines (VMs) in a public cloud, each costing \$0.10 per hour, and stores 500 GB of data at \$0.02 per GB per month.

  1. Compute cost:

    \$0.10 / hour × 10 VMs × 24 hours × 30 days = \$720 /month

  2. Storage cost:

    500 GB × \$0.02 / GB = \$10 /month

  3. Total monthly cost = $730

Formula (units shown):

Monthly Compute Cost (\$) = Hourly Rate (\$/hour) × Number of VMs × 24 hours × 30 days

Example 2 – Mixed IaaS + SaaS Scenario

A school uses:

  • 5 VMs for a virtual programming lab – $0.08 per hour each

  • Google Workspace for Education – $4 per user per month (200 users)

  • Backup storage of 1 TB at $0.015 per GB per month

Calculate the monthly cost.

  1. VM cost:

    \$0.08 × 5 × 24 × 30 = \$288 /month

  2. Google Workspace cost:

    200 users × \$4 = \$800 /month

  3. Backup storage cost:

    1 TB = 1024 GB → 1024 × \$0.015 = \$15.36 /month

  4. Total monthly cost = \$288 + \$800 + \$15.36 ≈ \$1,103.36

These examples let students practice:

  • Choosing the correct formula.

  • Converting units (GB ↔ TB).

  • Interpreting provider pricing tables – an essential AO2 & AO3 skill.

10. Suggested Diagram

Layered illustration (top‑down):

• Cloud Service Models – SaaS → PaaS → IaaS

• Each service model linked to the four Deployment Models (Public, Private, Hybrid, Community) with colour‑coding to show which combinations are possible.

• Include a brief legend (e.g., “Public‑SaaS = Google Workspace”).