Cloud computing
'The cloud' is a term used for services or infrastructure obtained via the internet. This includes internet-based services that store, manage and process data, rather than a local server or personal computer.
Cloud computing is usually classified as:
- Infrastructure as a Service (IaaS)
- Software as a Service (SaaS)
- Platform as a Service (PaaS)
Infrastructure as a Service (IaaS)
Providers offer computing infrastructure as a service to subscribers. IaaS includes cloud hosting of websites and virtual data centres, servers and Virtual Local Area Networks (VLANs).
Examples include: Amazon EC2, Windows Azure and Google Compute Engine.
IaaS can be summarised as: The base layer that provides storage (hard disks), servers and networks.
Platform as a Service (PaaS)
As the name suggests, PaaS provides computing platforms (a base on which to run applications) which typically include an operating system, an environment for programming, databases and virtual web servers.
Examples include: Windows Azure, Force.com, Google App Engine and Apache Stratos.
PaaS can be summarised as: A layer on top of IaaS, which provides the ability to run application software.
Software as a Service (SaaS)
Upon subscription, you are provided with access to application software. You don't have to worry about the installation, setup and running of the application. The service provider will do that for you.
Examples include: Google Apps and Microsoft Office 365.
SaaS can be summarised as: A layer on top of PaaS. Email applications (Gmail, Yahoo mail etc.) and social networking sites (Facebook, Twitter etc.) are further examples of SaaS.
Advantages and disadvantages of cloud computing
| Advantages | Disadvantages |
| Companies do not have to recruit and pay local IT staff for managing data. | Requires a very reliable network connection. |
| Data can be accessed from any device/anywhere with an internet connection. | Reliant on the cloud company continuing to operate. If the company folds, data may be lost. |
| Data can be accessed outside company buildings and work hours. | Companies may be charged for additional costs such as bandwidth usage and additional storage space. |
| No need for a company to purchase expensive servers. | Companies need to ensure that the cloud company is reputable and responsible as they still have to ensure compliance with data protection legislation. |
| Energy costs are reduced as companies are no longer running large servers and associated cooling fans. | |
| Data backups can be done automatically at frequent intervals. |
| Advantages | Companies do not have to recruit and pay local IT staff for managing data. |
|---|---|
| Disadvantages | Requires a very reliable network connection. |
| Advantages | Data can be accessed from any device/anywhere with an internet connection. |
|---|---|
| Disadvantages | Reliant on the cloud company continuing to operate. If the company folds, data may be lost. |
| Advantages | Data can be accessed outside company buildings and work hours. |
|---|---|
| Disadvantages | Companies may be charged for additional costs such as bandwidth usage and additional storage space. |
| Advantages | No need for a company to purchase expensive servers. |
|---|---|
| Disadvantages | Companies need to ensure that the cloud company is reputable and responsible as they still have to ensure compliance with data protection legislation. |
| Advantages | Energy costs are reduced as companies are no longer running large servers and associated cooling fans. |
|---|---|
| Disadvantages |
| Advantages | Data backups can be done automatically at frequent intervals. |
|---|---|
| Disadvantages |