☁️ What Is "The Cloud"?

Cloud Services Explorer

When people say "the cloud", they just mean someone else's computer. But there are different levels of cloud service — from renting a whole server to just using an app. See the difference.

DigiTech A-Level §2.3.3 CS A-Level Unit 3

🤔 Cloud = someone else's computer

Instead of buying and maintaining your own servers, you rent computing power from companies like Amazon (AWS), Microsoft (Azure), or Google Cloud. They handle the hardware — you just use it.

🍕 Analogy: Cooking at home (on-premise) vs ordering takeaway (SaaS) vs renting a kitchen (IaaS). Different levels of control and convenience.
🍕

The Pizza Model of Cloud Computing

This famous analogy explains the different service levels. Click each to see what you manage vs what the provider manages.

🏠
On-Premise
Cook at home
🖥️
IaaS
Rent a kitchen
🛠️
PaaS
Take & bake
📱
SaaS
Order delivery
📊

Who manages what?

Green = the cloud provider manages it. Blue = you manage it.

Layer🏠 On-Prem🖥️ IaaS🛠️ PaaS📱 SaaS
ApplicationsYouYouYouProvider
DataYouYouYouProvider
Runtime / MiddlewareYouYouProviderProvider
Operating SystemYouYouProviderProvider
Servers / StorageYouProviderProviderProvider
Networking / PhysicalYouProviderProviderProvider
📝 Exam tip: Remember: moving from left to right = you manage less, the provider manages more. IaaS = you still install and manage software. PaaS = you just write code. SaaS = you just use the app.