GOLDEN STARS MONTESSORI ACADEMYSubject: Data Processing
Class: Senior Secondary School 2 (S S 2)
Term: Second Term
Topic: Cloud Computing II: Understanding Service Models (SaaS, PaaS, IaaS)
In our previous lesson, we defined Cloud Computing as the delivery of computing services—including servers, storage, databases, networking, and software—over the Internet (“the cloud”). However, cloud computing is not a single "one-size-fits-all" technology. It is delivered in three main layers or service models. These models are often referred to as the Cloud Computing Stack because they build on top of one another.
Understanding these models—Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS)—is essential for knowing how businesses and individuals choose the right level of control and flexibility for their digital needs.
IaaS is the foundation of the cloud stack. It provides the "raw materials" of computing. Instead of a company buying expensive physical servers, hard drives, and networking cables to keep in their office (which requires electricity and cooling), they "rent" these resources from a provider like Amazon or Microsoft.
With IaaS, you are responsible for managing everything on top of the hardware: the operating system (like Windows or Linux), the applications, and the data. It is the most flexible model because it gives you total control over the infrastructure.
Example: Imagine you want to build a house. IaaS is like renting the land and the foundation. You still have to build the walls, put on the roof, and do the plumbing yourself, but you didn't have to go through the stress of clearing the forest or pouring the concrete base.
PaaS is the middle layer. It is designed specifically for software developers. It provides a framework that developers can build upon and use to create customized applications. All the hardware (servers/storage) and the operating system are managed by the provider.
The developer only focuses on writing the code for the application and managing the data. This allows developers to create apps quickly without worrying about setting up servers or updating the operating system.
Example: Using the house analogy, PaaS is like a pre-built workshop. The benches, electricity, and tools are already there. You just bring your wood and your skills to create the furniture (the application). You don't worry about maintaining the workshop building; you just focus on your craft.
SaaS is the most common cloud service used by everyday people. It delivers software applications over the internet, usually through a web browser or a mobile app. You do not need to install, update, or maintain the software on your computer; the provider handles everything.
You simply log in and use the service. You have the least amount of control over the technical side, but it is the most convenient because it is "ready to go."
Example: In our house analogy, SaaS is like staying in a hotel or renting a fully furnished apartment. You don't build anything, you don't bring tools, and you don't worry about the foundation. You just walk in, use the room, and pay for your stay.
To better understand these concepts, let’s look at how they appear in everyday Nigerian life and global tech:
When you log into Facebook, Instagram, or WhatsApp, you are using SaaS. You didn't build the app, and you don't manage the servers where your photos are stored. You simply use the software to communicate. Other examples include Gmail for emails and Canva for designing posters.
Imagine a developer in Lagos is hired to build a result-checking portal for your school. Instead of buying a server and installing a database manually, they use a service like Google App Engine or Heroku. These platforms provide the environment where the developer can write the code and host the portal instantly without being a hardware expert.
A new "FinTech" (Financial Technology) company needs to store massive amounts of banking data for millions of customers. They need high-level security and total control over their virtual servers. They rent space from Amazon Web Services (AWS) or Microsoft Azure. This is IaaS. They control the security settings and the operating system, but they don't have to physically touch a single wire or server machine.
How can you use these services today? Let’s look at the most accessible one: SaaS.
Instead of typing an assignment on a laptop and carrying it on a flash drive (which can get a virus), you can use Cloud Computing (SaaS).
docs.google.com.Objective: To visually demonstrate the difference between IaaS, PaaS, and SaaS using the "Pizza as a Service" analogy.
Materials Needed:
Procedure:
Activity: The Cloud Inventory