# Cloud Computing Unit 3 revision checklist

> An exam-day checklist for Cloud Computing Unit 3: architecture layers, deployment models, IaaS, PaaS and SaaS, storage types and charging models, with comparison tables and a self-test.

- Subject: Cloud Computing, Unit 3
- Published: 8 Nov 2026
- Status: editorial draft awaiting creator review

Use this page after you have watched the lesson or read the notes. Go through each list and say the answer out loud before you tick it; anything you can't explain is what to revisit.

The checklist follows the order of the Unit 3 lesson, so you can jump back to the matching part of the video or notes.

## Checklist

### Architecture
- [ ] I can name the four layers: application, platform, infrastructure and datacenter.
- [ ] I can say what each layer manages, with one example.
- [ ] I know virtualization (Xen, KVM, VMware) belongs to the infrastructure layer.

### Deployment models
- [ ] I can define public, private and hybrid cloud in one sentence each.
- [ ] I can explain why "public" doesn't mean free or visible to everyone.
- [ ] I can give two advantages and two limitations of each model.
- [ ] I can name the three private cloud types: shared, dedicated and dynamic.

### Service models
- [ ] I can say who manages what in IaaS, PaaS and SaaS.
- [ ] I can give one example of each: Amazon EC2, Google App Engine and Gmail.
- [ ] I know IaaS is also called Hardware as a Service.
- [ ] I can name the two SaaS categories: line-of-business and customer-oriented.

### Storage and charging
- [ ] I can list the four cloud storage types: personal, public, private and hybrid.
- [ ] I can explain the utility (pay-per-use) and subscription charging models.
- [ ] I can list at least three challenges cloud providers face.

## Deployment models in one table

| Model | Best for | Watch out for |
| --- | --- | --- |
| Public | Websites, blogs, batch jobs and other commodity workloads | Less control over security and customization |
| Private | Sensitive data and strict control or compliance needs | High cost and limited scalability |
| Hybrid | Keeping critical data private while using public scale | Complexity and cross-environment compliance |

## Service models in one table

| Model | What you rent | Example |
| --- | --- | --- |
| IaaS | Virtual machines, storage and networking | Amazon EC2, Amazon S3 |
| PaaS | A platform to build and run applications | Google App Engine, Microsoft Azure |
| SaaS | A finished application used over the internet | Gmail |

## Self-test

1. **Which layer of the cloud architecture looks after power supply and cooling?**
   Answer: The datacenter layer.
2. **What role does a hybrid cloud often play when an organization moves to the cloud?**
   Answer: It acts as an intermediate step, an on-ramp from the existing IT environment into the cloud.
3. **Which service model is most likely to lock you into one provider?**
   Answer: PaaS, because your application is built on the provider's runtime and tools.
4. **What type of cloud storage is Apple iCloud?**
   Answer: Personal (mobile) cloud storage.
5. **Name two benefits of cloud storage for backups.**
   Answer: Data is kept across distributed resources, so it survives a local hardware failure, and it supports disaster recovery without buying extra hardware.

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Published by Unique AppSites (https://www.uniqueappsites.com/), the channel by Anubhav Goel. Course codes and syllabi can change. Match the material to your current university scheme before relying on it for exam preparation.