Cloud computing involves a combination of data storage, computer processing and communications resources which are accessed through the internet by authorised subscribers. Cloud services can be public, private or a combination of both (hybrid). Often the cloud infrastructure will be located in a number of data centres across a wide geographical area; the resources will be interconnected to ensure high availability and resistance to faults.
Figure 3 – Different Devices Connect through the Cloud
This infrastructure collectively supports a wide range of commonly used services and software, operating on a variety of computer hardware and operating systems (e.g. the desktop PCs, laptops, tablets and smart phones shown in Figure 3). Indeed, some portable computers (e.g. the Google 'Chromebook') operate exclusively in the cloud.
Users of cloud computing can choose the appropriate combination of these resources to meet their particular needs, and access them at any time, from anywhere in the world – as long as they have an appropriately dimensioned and reliable connection to the internet.
The attraction of cloud computing for small businesses and organisations is that they are freed from the need to purchase and manage their own hardware and software, and can simply use what they need when they need to.
Cloud services are usually accessed via a web-browser-based interface; typical examples are shown in Figure 4.
Figure 4 – Typical Cloud Service Interface Screens
(sources: CTERA and Emantra)
The familiar 'point-and-click', 'drag-and-drop' functionality offered by these types of interface makes it relatively easy to add users and services to your system.