Cloud computing means storing and accessing data and programs over the Internet instead of your computer’s hard drive. The cloud is just a metaphor for the Internet. It goes back to the days of flowcharts and presentations that would represent the gigantic server-farm infrastructure of the Internet as nothing but a puffy, white cumulonimbus cloud, accepting connections and doling out information as it floats.
What cloud computing is not about is the hard drive. When you store data on or run programs from the hard drive, that’s called local storage and computing. Everything you need is physically close to you, which means accessing your data is fast and easy, for that one computer, or others on the local network. Working off your hard drive is how the computer industry functioned for decades; some would argue it’s still superior to cloud computing.
The cloud is also not about having dedicated network attached storage (NAS) hardware or server in residence. Storing data on a home or office network does not count as utilizing the cloud. (However, some NAS will remotely access things over the Internet).
For it to be considered “cloud computing,” you need to access your data or your programs over the Internet, or at the very least, have that data synchronized with other information over the Web. In a big business, you may know all there is to know about what’s on the other side of the connection; as an individual user, you may never have any idea what kind of massive data-processing is happening on the other end. The end result is the same: with an online connection, cloud computing can be done anywhere, anytime.
There are three different types of services can be delivered in the various cloud deployment environments: SaaS, PaaS and IaaS.
SaaS (Software as a Service): The consumer can use the provider’s software as a service through a thin client interface, such as a web browser. This is the visible part of Cloud Computing for the end user who no longer needs to set up the application on his desktop and can access his account through the web within a 100% secured environment.
PaaS (Platform as a Service): The consumer can deploy onto the infrastructure applications created using programming languages and tools supported by the provider. PaaS facilitates deployment of applications and provides all of the facilities require to support. It offers basic functions so that the developer does not need to worry about user management or availability issues.
IaaS (Infrastructure as a service): The consumer can provision processing, storage, networks, and other fundamental computing resources where he is able to deploy and run arbitrary software. In this case, the company can have, upon request, the ability to manage any application.