Computing paradigms: cloud and edge computing

Cloud computing

Cloud computing is on-demand access over the internet to computing resources (servers, storage, databases, software) held in remote data centres run by a provider, paid for as used.

Cloud infrastructure: data centres full of servers, storage arrays, networking, virtualisation (hypervisors and containers) and management software, often across many regions.

Cloud services:

• IaaS (Infrastructure as a Service): virtual machines, storage and networks; you manage the OS and software.
• PaaS (Platform as a Service): a ready platform to build and run your own apps without managing servers.
• SaaS (Software as a Service): finished applications used through a browser, such as webmail and online office suites.

Cloud: benefits and drawbacks

Benefits: no large up-front hardware cost; scalable up or down quickly; access from anywhere; the provider handles maintenance, backups and security patching; resilient across several data centres.

Drawbacks: needs a reliable internet connection; latency (distance to the data centre); ongoing costs; less control; data may be stored in another country, raising legal and privacy issues; reliance on one provider (lock-in) and outages affect many customers.

Edge computing

Edge computing processes data close to where it is produced, at the 'edge' of the network, instead of sending everything to a distant data centre.

Edge infrastructure: the devices themselves, edge gateways, local edge servers, micro data centres in factories, shops or mobile phone masts.

Edge services: real-time analytics and filtering, local decision-making, caching content close to users, running AI models on-device.

Benefits: low latency (vital for self-driving cars, industrial robots, AR); reduced bandwidth (only summaries are sent to the cloud); works if the connection drops; sensitive data can stay local.

Drawbacks: many distributed devices to manage, secure and update; limited processing power and storage at each site; higher hardware cost spread across many locations; physical security of devices in the field.

Worked example

A factory's machines produce 1 GB of vibration data per minute. Engineers want instant shutdown when a fault appears and monthly trend reports. Suggest an architecture.

1. An edge server in the factory analyses vibration in real time and shuts a machine down within milliseconds if a fault pattern appears: low latency and no dependence on the internet.
2. It sends only summaries and fault events to the cloud, saving bandwidth.
3. The cloud stores long-term data and runs heavy analytics for the monthly trend reports.

Answer: Edge for real-time control, cloud for storage and long-term analysis.

Check yourself

1. A school uses a web-based email and document service it does not install or manage. What type of cloud service is this?
   • IaaS
   • PaaS
   • SaaS
   • Edge computing
   Show answer

   SaaS. Finished software delivered over the internet is SaaS.

2. A start-up rents virtual servers and installs its own operating system and software on them. Which service model is this?
   • IaaS
   • SaaS
   • PaaS
   • DNS
   Show answer

   IaaS. Raw virtual infrastructure is IaaS.

3. What is edge computing?
   • Storing all data in one central server
   • Using only wired networks
   • Processing data close to where it is produced instead of in a distant data centre
   • Running software through a web browser
   Show answer

   Processing data close to where it is produced instead of in a distant data centre. The 'edge' of the network is near the devices.

4. Why does a self-driving car rely on edge computing rather than the cloud for braking decisions?
   • The cloud cannot store images
   • Sending data to a distant data centre and back adds delay that could be dangerous
   • Edge devices have unlimited processing power
   • Cloud computing is illegal in vehicles
   Show answer

   Sending data to a distant data centre and back adds delay that could be dangerous. Real-time safety decisions need very low latency.

5. Which is a benefit of cloud computing for a small business?
   • It works without an internet connection
   • Data always stays in the business's own country
   • There are no ongoing costs
   • Resources can be scaled up or down quickly without buying hardware
   Show answer

   Resources can be scaled up or down quickly without buying hardware. Pay-as-you-go scalability is a key cloud benefit.

6. Which is a drawback of edge computing?
   • Latency is very high
   • Many distributed devices must each be secured and updated
   • It needs more bandwidth than the cloud
   • It cannot process data locally
   Show answer

   Many distributed devices must each be secured and updated. Management and security are harder across many sites.

7. Why might storing data in the cloud raise legal concerns?
   • Cloud data cannot be encrypted
   • Cloud providers own all data uploaded
   • The cloud deletes data after a month
   • The data may be held in another country with different data protection laws
   Show answer

   The data may be held in another country with different data protection laws. Data location affects which laws apply.

Practise with instant feedback Print this lesson

Sources

• Pearson Edexcel International Advanced Subsidiary and Advanced Level in Computer Science specification (2026), Issue 1
• Pearson Edexcel IAL Computer Science sample assessment materials (Unit 3 paper, resource booklet and mark scheme)

Last updated 8 November 2026. Spotted a mistake? Tell us.