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

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

Objective: Understand the Characteristics, Uses and Issues of Cloud Computing

Cloud computing is a network-based model that provides on-demand access to shared resources such as servers, storage, applications and services. It allows users to access and use these resources over the internet without having to manage the underlying infrastructure.

Key Characteristics of Cloud Computing

  • On‑Demand Self‑Service: Users can provision computing resources automatically without human intervention from the provider.
  • Broad Network Access: Services are available over the network and accessed through standard mechanisms such as web portals or APIs.
  • Resource Pooling: Provider’s resources are pooled to serve multiple consumers using a multi‑tenant model.
  • Rapid Elasticity: Resources can be elastically provisioned and released to scale quickly.
  • Measured Service: Resource usage is monitored, controlled and reported, providing transparency for both provider and consumer.

Cloud Deployment Models

Deployment Model Definition Typical Users
Public Cloud Services offered over the public internet and available to anyone. Small businesses, individuals, large enterprises.
Private Cloud Cloud infrastructure operated solely for a single organisation. Government agencies, large enterprises with strict security.
Hybrid Cloud Combination of public and private clouds linked by technology. Businesses needing flexibility and cost‑efficiency.
Community Cloud Shared by several organisations with common concerns. Industry groups, research consortia.

Cloud Service Models

Service Model What is Provided Example Services
Infrastructure as a Service (IaaS) Virtualised computing resources over the internet. Amazon EC2, Microsoft Azure \cdot irtual Machines.
Platform as a Service (PaaS) Platform allowing customers to develop, run and manage applications. Google App Engine, Heroku.
Software as a Service (SaaS) Software delivered over the internet on a subscription basis. Google Workspace, Microsoft 365.

Benefits of Cloud Computing

  • Cost Efficiency: Pay‑as‑you‑go pricing reduces capital expenditure.
  • Scalability: Resources can be scaled up or down quickly.
  • Accessibility: Access data and applications from any device with internet.
  • Reliability: Redundant infrastructure improves uptime.
  • Focus on Core Business: Offloads IT maintenance to the provider.

Common Issues and Risks

  1. Security: Data may be exposed if not properly protected.
  2. Privacy: Compliance with data protection laws (e.g., GDPR).
  3. Vendor Lock‑In: Difficulty migrating services between providers.
  4. Downtime: Dependence on provider’s uptime guarantees.
  5. Data Transfer Costs: Bandwidth charges for moving data in and out.

Security Measures in Cloud Environments

  • Encryption of data at rest and in transit.
  • Identity and access management (IAM) policies.
  • Regular security audits and compliance certifications.
  • Multi‑factor authentication (MFA).
  • Network segmentation and firewalls.

Calculating Cloud Costs – Example

Suppose a company uses 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 × 10 × 24 × 30 = $720 per month.
  2. Storage cost: 500 × $0.02 = $10 per month.
  3. Total monthly cost: $720 + $10 = $730.

Formula for monthly compute cost:

$\text{Monthly Cost} = \text{Hourly Rate} \times \text{Number of \cdot Ms} \times 24 \times 30$

Suggested Diagram

Suggested diagram: Cloud deployment and service model relationships.