Cloud computing means accessing computing resources — storage, software, processing power — over the internet, hosted on remote servers run by a provider, rather than on your own device or local network. The "cloud" is simply a metaphor for remote servers you never see but constantly use.
What is the analogy for cloud computing?
Electricity is the classic analogy. A century ago, factories had to build and maintain their own power generators. Today, every building plugs into the national grid and pays for only the electricity it uses — the generators, cables, and maintenance are someone else's problem. Cloud computing does the same for IT: instead of buying and managing your own servers, you plug into a remote infrastructure and pay for what you consume. The complexity is hidden; you get the benefit.
What are the three main service models?
Cloud services are typically described using three models, differing in how much the provider manages for you:
| Model | Full name | What the provider gives you | You manage | Examples |
|---|---|---|---|---|
| IaaS | Infrastructure as a Service | Virtual servers, storage, networking | Operating system, apps, data | AWS EC2, Microsoft Azure VMs |
| PaaS | Platform as a Service | Runtime, database, development tools | Application code and data | Google App Engine, Heroku |
| SaaS | Software as a Service | Complete applications, ready to use | Your data and user settings only | Google Docs, Microsoft 365, Spotify |
At KS3, you are most likely to encounter SaaS: software you access through a browser without installing anything — Google Classroom, OneDrive, iCloud, and Netflix are all SaaS products.
What are the main advantages of cloud computing?
| Advantage | Explanation |
|---|---|
| Accessibility | Access your files and apps from any device with an internet connection |
| Automatic backups | Cloud providers replicate data across multiple locations — loss of one device does not mean loss of data |
| Cost | No large upfront hardware purchase; pay monthly for what you use |
| Scalability | Instantly scale up (more storage, more computing) as needs grow |
| Automatic updates | Software is updated centrally; users always have the latest version |
| Collaboration | Multiple users can edit the same document simultaneously in real time |
What are the disadvantages and risks?
| Disadvantage | Explanation |
|---|---|
| Internet dependency | No connection = no access; local storage is available offline |
| Privacy concerns | Your data is stored on servers controlled by a third party in potentially another country |
| Security risks | A breach at the cloud provider could expose many users' data simultaneously |
| Ongoing cost | Subscription fees accumulate; local storage is a one-off cost |
| Limited control | If the provider changes pricing, terms, or discontinues a service, users are affected |
| Latency | Network round-trip time can make some applications slower than local equivalents |
Where is cloud data physically stored?
Despite the ethereal name, cloud data lives in enormous physical buildings called data centres — warehouses packed with thousands of servers, maintained at cool temperatures, and connected to multiple redundant power supplies and internet connections. Major providers (Amazon, Google, Microsoft) operate data centres on every continent. UK organisations storing personal data under UK GDPR must be mindful of which country's data centres hold that data, as different legal protections apply.
What is the difference between public, private, and hybrid cloud?
| Type | Who uses it | Control | Cost |
|---|---|---|---|
| Public cloud | General public; shared infrastructure | Low — provider controls | Low — shared costs |
| Private cloud | One organisation; dedicated infrastructure | High — organisation controls | High — dedicated hardware |
| Hybrid cloud | Mix of both | Variable | Variable |
Schools typically use public cloud (Google Workspace, Microsoft 365). Hospitals and banks often use private or hybrid cloud to keep sensitive data under tighter control.
Frequently asked questions
Is cloud storage the same as cloud computing?
Cloud storage (e.g. Google Drive, OneDrive, iCloud) is one specific cloud service — storing and retrieving files remotely. Cloud computing is the broader concept encompassing storage, software, processing, databases, and more delivered over the internet. Cloud storage is a type of cloud computing, not a synonym for it.
What happens to my data if a cloud provider goes out of business?
This is a genuine risk. Responsible providers give notice and allow time to download data before shutdown, but there is no universal guarantee. The practical mitigation is to keep a local backup of critical data (following the 3-2-1 rule: three copies, two different media types, one offsite) rather than relying solely on any single cloud provider.
Is the cloud more secure than local storage?
It depends. Cloud providers invest heavily in security — physical security at data centres, encryption in transit and at rest, and specialist security teams — which most individuals and small organisations cannot match. However, concentrating millions of users' data on a single platform creates a high-value target for attackers. A local hard drive sitting in a drawer is harder for a remote attacker to access, but far more vulnerable to physical theft, fire, or hardware failure. Real security uses both.
How does cloud computing affect the environment?
Data centres consume enormous amounts of electricity — globally, they account for roughly 1–2% of world electricity use. Cooling systems, in particular, require significant energy. Major providers (Google, Microsoft, Amazon) have committed to carbon-neutral or net-zero targets and increasingly power data centres with renewable energy. However, rapidly growing AI workloads are increasing energy demand faster than efficiency gains. Environmental impact is a growing ethical consideration in cloud computing.
Explore cloud computing and digital systems with Professor Turing's Socratic question sessions at aitutors.me.