Cloud computing is a core concept in IB Computer Science because it explains how modern software and services are delivered over the internet. Students are expected to understand what cloud computing is, how it works, and most importantly, the three main cloud service models: SaaS, PaaS, and IaaS.
Many students confuse these models because they sound similar. In IB exams, clear comparison and correct examples are essential for full marks.
What Is Cloud Computing?
Cloud computing refers to delivering:
- Software
- Platforms
- Infrastructure
over the internet instead of running them locally on a personal computer or server.
Key characteristics of cloud computing include:
- On-demand access
- Scalability
- Remote access
- Reduced need for local hardware
The difference between SaaS, PaaS, and IaaS lies in how much control the user has.
Software as a Service (SaaS)
SaaS provides fully finished software that users access via the internet.
With SaaS:
- The provider manages everything
- Users only use the software
- No installation is required
Examples include:
- Web-based email
- Online document editors
- Cloud-based learning platforms
In IB Computer Science, SaaS is often linked to:
- Ease of use
- Minimal technical responsibility
- Subscription-based access
Users cannot control the underlying system — they simply use the application.
Platform as a Service (PaaS)
PaaS provides a platform for developing and running applications.
With PaaS:
- The provider manages hardware and operating systems
- Users manage applications and code
- Developers can focus on programming
PaaS is commonly used for:
- Web application development
- Software testing
- Collaborative development
In IB terms, PaaS sits between SaaS and IaaS in terms of control.
Infrastructure as a Service (IaaS)
IaaS provides virtualised hardware resources over the internet.
With IaaS:
- Users control operating systems
- Users manage applications and data
- The provider supplies servers, storage, and networking
IaaS is often used for:
- Hosting websites
- Running custom server configurations
- Scalable enterprise systems
It offers the most flexibility, but also the most responsibility.
Comparing SaaS, PaaS, and IaaS
For IB Computer Science, students should compare models based on control:
- SaaS: Least control, easiest to use
- PaaS: Moderate control, developer-focused
- IaaS: Most control, infrastructure-focused
Clear comparisons score higher than isolated definitions.
Why Cloud Models Matter in IB Computer Science
These models explain:
- How modern software is delivered
- Why businesses choose cloud services
- Trade-offs between control and convenience
They also appear in questions about cost, scalability, and security.
Common Student Mistakes
Students often:
- Mix up SaaS and PaaS
- Forget who manages what
- Use vague examples
- Describe cloud computing without mentioning service models
Precision matters.
Final Thoughts
SaaS, PaaS, and IaaS represent different levels of cloud service, from ready-to-use software to fully custom infrastructure. Understanding who controls what in each model is the key to mastering cloud computing in IB Computer Science.
This clarity allows students to explain modern computing systems accurately and confidently in exams.
