Cloud Computing

Cloud computing provides the IT infrastructure to develop, host or run services and applications on demand over the Internet. It also provides resources to store data. Cloud-computing providers typically offer these services on a pay-as-you-go basis and users can scale them up and down to meet their needs.

There are three types of cloud service:

Software as a Service (SaaS)

Software as a service refers to software or applications that users access over the Internet (typically from a public cloud or shared environment). As a result, users don’t need to install SaaS applications, unlike desktop applications. Microsoft Office 365 is an example of SaaS.

Infrastructure as a Service (IaaS)

Infrastructure as a service refers to computing infrastructure – such as CPU, RAM, storage, virtual servers and network equipment – that users access over the Internet. The model works as a virtual data centre that users can access on demand. It provides users with computing as a service and removes the need for them to purchase and manage expensive IT infrastructure. As with most cloud services, users can scale it up and down and usually only pay for what they consume.

Platform as a Service (PaaS)

PaaS refers to a hosted environment in which developers can build and launch new applications. Well known cloud platforms include Microsoft Azure, Amazon EC2 and Force.com.

The most common ways to deploy cloud services are:

Public cloud

A public cloud generally provides cloud services to anyone over the Internet. Many users will share a public cloud, which means they get good value for money owing to the economies of scale involved.

Private cloud

A private cloud is generally restricted to a single customer or trusted community. These are popular with organisations that want to benefit from cloud computing, but need more security and flexibility than a public cloud can offer. Organisations can run private clouds in their own data centres or in data centres hosted by a third party.

Hybrid cloud

A hybrid cloud, as the name infers, is a cloud that joins on-premises infrastructure to private or public clouds, or clouds to each other.